Concerns over air pollution in the city centre means Cardiff will hold its first car-free day on Thursday.

But only Park Place in Cathays will be closed to all traffic until 00:00 BST on Friday.
It will become a street market and host a transport exhibition giving information on sustainable travel.
While all commuters will be encouraged to leave their cars at home in a move designed to combat air pollution, no other areas will be closed off.
Jane Lorimer, director of cycle charity Sustrans Cymru said it was a "positive first step".
Councillors backed plans to ban cars in the city centre for one day each year, to cut air pollution, last October.
But cabinet member Ramesh Patel said it would be "grossly irresponsible" to widen the area before the first plan had been reviewed.
He added: "With the new bus interchange developing, a cycling strategy being produced, planned investment in our railways and future plans for the metro, sustainable transport is a major priority for the council.
"Making walking, cycling and public transport more attractive and viable options for commuters and residents are integral to Cardiff's continued development and achieving our aspiration to become Europe's most liveable capital city."
Car-free days already take place in Delhi, Paris and London.
It is claimed air pollution is linked to tens of thousands of deaths in the UK annually.


BBC News environment correspondent Richard Black traces key milestones, scientific discoveries, technical innovations and political action.

1712 - British ironmonger Thomas Newcomen invents the first widely used steam engine, paving the way for the Industrial Revolution and industrial scale use of coal.
1800 - World population reaches one billion.
1824 - French physicist Joseph Fourier describes the Earth's natural "greenhouse effect". He writes: "The temperature [of the Earth] can be augmented by the interposition of the atmosphere, because heat in the state of light finds less resistance in penetrating the air, than in re-passing into the air when converted into non-luminous heat."
1861 - Irish physicist John Tyndall shows that water vapour and certain other gases create the greenhouse effect. "This aqueous vapour is a blanket more necessary to the vegetable life of England than clothing is to man," he concludes. More than a century later, he is honoured by having a prominent UK climate research organisation - the Tyndall Centre - named after him.
1886 - Karl Benz unveils the Motorwagen, often regarded as the first true automobile.
1896 - Swedish chemist Svante Arrhenius concludes that industrial-age coal burning will enhance the natural greenhouse effect. He suggests this might be beneficial for future generations. His conclusions on the likely size of the "man-made greenhouse" are in the same ballpark - a few degrees Celsius for a doubling of CO2 - as modern-day climate models.
1900 - Another Swede, Knut Angstrom, discovers that even at the tiny concentrations found in the atmosphere, CO2 strongly absorbs parts of the infrared spectrum. Although he does not realise the significance, Angstrom has shown that a trace gas can produce greenhouse warming.
1927 - Carbon emissions from fossil fuel burning and industry reach one billion tonnes per year.
1930 - Human population reaches two billion.
1938 - Using records from 147 weather stations around the world, British engineer Guy Callendar shows that temperatures had risen over the previous century. He also shows that CO2 concentrations had increased over the same period, and suggests this caused the warming. The "Callendar effect" is widely dismissed by meteorologists.
1955 - Using a new generation of equipment including early computers, US researcher Gilbert Plass analyses in detail the infrared absorption of various gases. He concludes that doubling CO2 concentrations would increase temperatures by 3-4C.
1957 - US oceanographer Roger Revelle and chemist Hans Suess show that seawater will not absorb all the additional CO2 entering the atmosphere, as many had assumed. Revelle writes: "Human beings are now carrying out a large scale geophysical experiment..."
1958 - Using equipment he had developed himself, Charles David (Dave) Keeling begins systematic measurements of atmospheric CO2 at Mauna Loa in Hawaii and in Antarctica. Within four years, the project - which continues today - provides the first unequivocal proof that CO2 concentrations are rising.
1960 - Human population reaches three billion.
1965 - A US President's Advisory Committee panel warns that the greenhouse effect is a matter of "real concern".
1972 - First UN environment conference, in Stockholm. Climate change hardly registers on the agenda, which centres on issues such as chemical pollution, atomic bomb testing and whaling. The United Nations Environment Programme (Unep) is formed as a result.
1975 - Human population reaches four billion.
1975 - US scientist Wallace Broecker puts the term "global warming" into the public domain in the title of a scientific paper.
1987 - Human population reaches five billion
1987 - Montreal Protocol agreed, restricting chemicals that damage the ozone layer. Although not established with climate change in mind, it has had a greater impact on greenhouse gas emissions than the Kyoto Protocol.
1988 - Intergovernmental Panel on Climate Change (IPCC) formed to collate and assess evidence on climate change.
1989 - UK Prime Minister Margaret Thatcher - possessor of a chemistry degree - warns in a speech to the UN that "We are seeing a vast increase in the amount of carbon dioxide reaching the atmosphere... The result is that change in future is likely to be more fundamental and more widespread than anything we have known hitherto." She calls for a global treaty on climate change.
1989 - Carbon emissions from fossil fuel burning and industry reach six billion tonnes per year.
1990 - IPCC produces First Assessment Report. It concludes that temperatures have risen by 0.3-0.6C over the last century, that humanity's emissions are adding to the atmosphere's natural complement of greenhouse gases, and that the addition would be expected to result in warming.
1992 - At the Earth Summit in Rio de Janeiro, governments agree the United Framework Convention on Climate Change. Its key objective is "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system". Developed countries agree to return their emissions to 1990 levels.
1995 - IPCC Second Assessment Report concludes that the balance of evidence suggests "a discernible human influence" on the Earth's climate. This has been called the first definitive statement that humans are responsible for climate change.
1997 - Kyoto Protocol agreed. Developed nations pledge to reduce emissions by an average of 5% by the period 2008-12, with wide variations on targets for individual countries. US Senate immediately declares it will not ratify the treaty.
1998 - Strong El Nino conditions combine with global warming to produce the warmest year on record. The average global temperature reached 0.52C above the mean for the period 1961-90 (a commonly used baseline).
1998 - Publication of the controversial "hockey stick" graph indicating that modern-day temperature rise in the northern hemisphere is unusual compared with the last 1,000 years. The work would later be the subject of two enquiries instigated by the US Congress.
1999 - Human population reaches six billion.
2001 - President George W Bush removes the US from the Kyoto process.
2001 - IPCC Third Assessment Report finds "new and stronger evidence" that humanity's emissions of greenhouse gases are the main cause of the warming seen in the second half of the 20th Century.
2005 - The Kyoto Protocol becomes international law for those countries still inside it.
2005 - UK Prime Minister Tony Blair selects climate change as a priority for his terms as chair of the G8 and president of the EU.
2006 - The Stern Review concludes that climate change could damage global GDP by up to 20% if left unchecked - but curbing it would cost about 1% of global GDP.
2006 - Carbon emissions from fossil fuel burning and industry reach eight billion tonnes per year.
2007 - The IPCC's Fourth Assessment Report concludes it is more than 90% likely that humanity's emissions of greenhouse gases are responsible for modern-day climate change.
2007 - The IPCC and former US vice-president Al Gore receive the Nobel Peace Prize "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change".
2007 - At UN negotiations in Bali, governments agree the two-year "Bali roadmap" aimed at hammering out a new global treaty by the end of 2009.
2008 - Half a century after beginning observations at Mauna Loa, the Keeling project shows that CO2 concentrations have risen from 315 parts per million (ppm) in 1958 to 380ppm in 2008.
2008 - Two months before taking office, incoming US president Barack Obama pledges to "engage vigorously" with the rest of the world on climate change.
2009 - China overtakes the US as the world's biggest greenhouse gas emitter - although the US remains well ahead on a per-capita basis.
2009 - Computer hackers download a huge tranche of emails from a server at the University of East Anglia's Climatic Research Unit and release some on the internet, leading to the "ClimateGate" affair.
2009 - 192 governments convene for the UN climate summit in Copenhagen with expectations of a new global agreement high; but they leave only with a controversial political declaration, the Copenhagen Accord.
2010 - Developed countries begin contributing to a $30bn, three-year deal on "Fast Start Finance" to help them "green" their economies and adapt to climate impacts.
2010 - A series of reviews into "ClimateGate" and the IPCC ask for more openness, but clear scientists of malpractice.
2010 - The UN summit in Mexico does not collapse, as had been feared, but ends with agreements on a number of issues.
2011 - A new analysis of the Earth's temperature record by scientists concerned over the "ClimateGate" allegations proves the planet's land surface really has warmed over the last century.
2011 - Human population reaches seven billion.
2011 - Data shows concentrations of greenhouse gases are rising faster than in previous years.
2012 - Arctic sea ice reaches a minimum extent of 3.41 million sq km (1.32 million sq mi), a record for the lowest summer cover since satellite measurements began in 1979.
2013 - The Mauna Loa Observatory on Hawaii reports that the daily mean concentration of CO2 in the atmosphere has surpassed 400 parts per million (ppm) for the first time since measurements began in 1958.
2013 - The first part of the IPCC's fifth assessment report says scientists are 95% certain that humans are the "dominant cause" of global warming since the 1950s.


The prototype for a new Welsh-made hydrogen-powered car has been unveiled.

The two-seater Rasa was developed in Llandrindod Wells, Powys, by Riversimple Movement Ltd.
Its road-legal prototype does 0-60mph (96kmh) in 10 seconds, with its only output water.
The Rasa, which received a Â£2m Welsh grant in 2015, will go on trial for 12 months later this year, with the final model set for release in 2018.
Hugo Spowers, founder of Riversimple, said the prototype marked a "key milestone" in bringing the Rasa to market.
"The car is simple, light and fun in every respect," he said.
If the trial - to be funded by a Â£1.6m European Union grant - proves successful, the firm has said the next step would be to set up volume production in a factory employing 220 people.
Riversimple believes the Rasa will be the most efficient vehicle in the world.
Weighing 580kg (91 stone) - about the half the weight of a small petrol or diesel car - it has a potential range of up to 300 miles (482 km) on 1.5kg of hydrogen - a fuel-economy equivalent of 250mpg.
The car has a top speed of 60 mph (96kmh).
It works by passing hydrogen through the fuel cell, where it combines with oxygen to form water and electricity to drive motors positioned in each of the four wheels.
Prof Garel Rhys, who is part of the Welsh government's steering group on the low-carbon vehicle sector, said the company was "at the forefront".
"Hydrogen fuel cell technology is in its infancy," he added, "and they (Riversimple) are at the cutting-edge".
Prof Peter Wells, of the Centre for Automotive Industry Research and Cardiff Business School, said the team had reduced the weight of the car to the "absolute minimum".
"This allows it to run on a very small fuel cell, compared to the big car manufacturers," he said.
The car will not be sold but offered under a leasing agreement, with repairs, maintenance, insurance and fuel expenses covered by a fixed monthly-fee, with the aim of lowering the cost of hydrogen-powered motoring.


The so-called Islamic State group is facing its "end game" in the Iraqi city where its campaign of violence began in 2014, the defence secretary has said.

Sir Michael Fallon said the RAF had hit more than 700 targets in support of the liberation of Mosul by Iraqi forces.
IS is also losing ground in its Syrian stronghold of Raqqa, Sir Michael said.
He was speaking before a Nato meeting where he is expected to confirm 85 more UK troops will be sent to Afghanistan on training duties.
There are already 500 British personnel in the country.
The US-led coalition against IS has been stepping up airstrikes in recent months, with the RAF now working at its highest operational tempo in 25 years.
UK forces have also hit 69 targets in support of Syrian Democratic Forces in Raqqa, where Sir Michael said there is "irreversible momentum and progress" towards the defeat of IS.
The UK has also been using "offensive" cyber attacks against IS.
The Ministry of Defence said the UK commitment to the Afghan training mission was part of a global effort to counter terror and build stability.
Sir Michael Fallon said: "Keeping Afghanistan from becoming a safe haven for transnational terrorists helps to keep our streets safe too.
"That's why we're stepping up our support to the government of Afghanistan and its defence forces, helping them to expand security and develop their armed forces."


The body of Kim Jong-nam, half brother of North Korean leader Kim Jong-un, has arrived in Pyongyang, Chinese officials say.

North Korea had requested the body, but has not confirmed its identity.
It was released as part of a deal under which nine Malaysians previously prevented from leaving North Korea have now arrived home.
The two countries had been locked in a diplomatic row in the wake of Mr Kim's murder in Kuala Lumpur last month.
Both countries had banned each other's citizens from leaving.
"The body of the DPRK citizen who died in Malaysia and relevant DPRK citizens have returned to the DPRK today via Beijing," Chinese foreign ministry spokesman Lu Kang said during a regular press briefing, using the country's official name, the Democratic People's Republic of Korea.
North Korea is widely suspected of having orchestrated the killing with a nerve agent in Kuala Lumpur's airport.
Three North Koreans who had been wanted for questioning have now been allowed to leave Malaysia, Malaysia's chief of police said.
"We have obtained whatever we wanted from them'' and are "satisfied" with the statements, Khalid Abu Bakar said.
In the wake of Mr Kim's killing on 13 February, Pyongyang reacted angrily when Malaysia refused to hand over the body immediately, without an autopsy.
Malaysian authorities said they had the right to conduct an autopsy as he had been killed on Malaysian soil, and that they would only release the body to Mr Kim's family.
On Thursday, Mr Najib said a formal request had been received from the family, but gave no further details.
A day later, national police chief Khalid Abu Bakar said "legally speaking, Kim Jong Un is the next-of-kin" but declined to say who the request had come from.
King Jong-nam's own family previously lived in Macau but they are now thought to be in hiding.
His son Kim Han-sol appeared in a video earlier this month confirming he was with his mother and sister at an unspecified location.
Although he was the eldest son of the former North Korean leader Kim Jong-il, Kim Jong-nam was passed over for the leadership and was living outside North Korea at the time of his father's death.
Malaysia's refusal to hand over the body prompted a war of words. North Korea's ambassador Kang Chol accused Malaysia of colluding with "hostile forces", allegations which Kuala Lumpur dubbed as "delusions, lies and half-truths".
Kang Chol was expelled and the Malaysian ambassador to North Korea was also recalled.
Pyongyang then said it would ban all Malaysians in North Korea from leaving until the "situation was resolved", which Malaysia's Prime Minister Najib Razak called an "abhorrent act" that effectively held his citizens hostage.
Kuala Lumpur enacted a tit-for-tat exit ban on North Koreans.
Under the deal, the nine Malaysian nationals returned to Kuala Lumpur early on Friday, where they were met by relatives.
They include the country's counsellor to North Korea, Mohd Nor Azrin Md Zain, embassy staff, and their families.
The exact circumstances of how the deal was struck remain unclear. Malaysia's Prime Minister Najib Razak described the negotiations as "challenging".
Foreign Minister Anifah Aman hailed the exchange as a success of diplomacy and "level-headedness".
Reuters reported that television footage showed two North Koreans on the flight to Beijing with the body: Hyon Kwang Song, the second secretary at the North Korean embassy in Kuala Lumpur, and Kim Uk Il, a North Korean state airline employee.
The third was named Ri Ji U, who had been holed up with them in the North Korean Embassy, Reuters quoted the chief of police as saying.


Almost one in five parents in the UK is being asked to set up payments to their children's schools, as head teachers warn of budget shortages, says a survey from a teachers' union.

The NASUWT survey claims some parents are asked for £400 or more per year.
Schools in England have been warning of cash shortages and the union says schools are now depending on parents.
But the Department for Education says "no parent is required to make a contribution".
Teachers' unions are holding their conferences over the Easter bank holiday weekend, with funding one of the biggest issues.
The National Union of Teachers, meeting in Cardiff, will hear warnings on Saturday about the impact of cash shortages.
The survey from the NASUWT survey, holding its annual conference in Manchester, claims that schools are increasingly relying on money from parents.
Based on almost 4,000 responses, the survey says 18% of parents have been asked to sign up for direct debits or standing orders for their children's school, typically of about £50 per year.
But more than one in 20 parents with children in state schools were paying £400 or above.
A further 13% of parents had been asked to make donations in cash or cheques.
Your comments on schools asking parents to top up their budgets:
"She's only been there a term, but there seems to be a letter home at least once a week asking for money," a parent told the NASUWT survey.
"The school asks for a 'voluntary contribution' but if you forget to pay you are sent texts telling you that you haven't paid," said another parent.
There were other financial costs for parents, such as a laptop for homework and music lessons.
"We have not allowed them to do music at school as they need to provide their own instruments," said a parent, quoted in the survey.
Over a quarter of parents said their child had been unable to take part in a trip or excursion because of the cost.
"Ski trip was £600. French trip £450. These are for less than a week. They are beyond my funds," a parent told the survey.
The union's leader Chris Keates said that "access to education must not be based on parents' ability to pay".
This week the Sutton Trust education charity warned of schools cutting staff because of financial pressure.
The Public Accounts Committee has said that standards are threatened by school budget cuts of £3bn.
A lobby of Parliament over funding, by teachers' unions and parents' campaign groups, has been announced for early June.
Kevin Courtney, NUT general secretary, reminded the government of a manifesto commitment to parents that "the money that follows their children into schools will be protected".
"In half of the schools in the country the money following your child into schools has been dramatically cut in cash terms, and in the other half it's been cut in real terms," he said.
A Department for Education spokeswoman said: "No parent is required to make a contribution to their child's education, the rules are clear on this and no policies have been introduced by this government to allow schools to charge parents."
The spokeswoman said school funding was at record levels, but "we recognise schools are facing cost pressures."


New York City Police Commissioner Bill Bratton - the most prominent law enforcement officer in the US - will step down in September.

Mayor Bill de Blasio announced Mr Bratton's retirement on Tuesday, saying his accomplishments were "inestimable and extraordinary".
Mr Bratton, 68, had previously said he would not serve after 2017.
Protesters linked to the Black Lives Matter group had called for him to be fired.
On Monday more than 100 people gathered at a New York rally to protest against what they said was racial bias by the police.
Mr Bratton previously led police departments in Boston and Los Angeles. He also ran the New York Police Department from 1994 to 1996 under then-Mayor Rudy Giuliani.
He is known for his aggressive efforts to combat crime in the 1990s, in accordance with "broken windows theory", which advocates dealing strongly with low-level anti-social behaviour as a way to prevent more serious crime.
He was given the moniker "Supercop" when he helped UK police after riots five years ago.
Mr Bratton was a strong opponent of the stop-and-frisk tactics used by his predecessor, which he said unfairly targeted black and Hispanic people.
But his "broken windows" policy attracted criticism.
In December 2014, an unarmed black man, Eric Garner, was confronted by police while allegedly selling stolen cigarettes. He died in a policeman's chokehold. The white officer, Daniel Pantaleo, was not indicted.
The NYPD's top uniformed officer, Chief James O'Neill, will replace Mr Bratton.
Mr O'Neill, who like Mr Bratton is white, has worked for the NYPD for 30 years and was instrumental in building its neighbourhood policing programme.
Mr Bratton welcomed his successor's appointment, saying: "Jim O'Neill's acumen as a tough cop was honed in the subways, the streets, and later running precincts, narcotics and fugitive apprehension.
"Few understand the human side of policing better than Jim O'Neill."
Mr de Blasio said: "We will never forget or fail to honour the achievements of Bill Bratton."


A 77-year-old man has shot three people at the senior citizens' complex where he lived in the US state of Wyoming, killing one person and wounding two.

Larry Rosenberg, who was armed with a rifle and a handgun, was upset about a poker game at the facility in the city of Cheyenne, said another resident.
The suspect fled the scene by bicycle, killing himself as police closed in.
Shootings are rare in the city - police handled a total of six homicide cases last year.
Mary Eastman, 80, said Rosenberg left a suicide note with her that morning.
"His problem really was that damned poker gambling," she said, referring to card games in the home's common room.
"That was it. That was all he complained about."
Police have confirmed that they are examining a "letter of discontent" by the gunman, but they did not disclose further details.
Investigators said all the victims were known to Rosenberg, and there had been a "long-standing animosity" between the men.
Mrs Eastman's daughter told local media that Rosenberg had become more withdrawn recently at the Heritage Court Apartments complex.
"He started getting more and more distant, complaining about the facility and about people and just kind of pulling away, isolating himself more and more," said the daughter.
Schools in Cheyenne were placed on lockdown for a brief time.
Cheyenne, the capital of Wyoming, has a population of 60,000.


A common drug could hold the key to long life, in flies at least, according to research.

At low doses, lithium prolonged the life of fruit flies in lab experiments.
Scientists say the finding is "encouraging" and could eventually lead to new drugs to help people live longer and healthier lives.
Lithium is used in psychiatry to help stop mood swings but has a risk of serious side-effects at high doses.
How lithium acts on the brain is not fully understood, but in fruit flies the drug seems to extend life by blocking a chemical known as GSK-3.
"The response we've seen in flies to low doses of lithium is very encouraging and our next step is to look at targeting GSK-3 in more complex animals with the aim of eventually developing a drug regime to test in humans," said Prof Linda Partridge of the UCL Institute of Healthy Ageing, who led the study.
The research, published in Cell Reports, found fruit flies lived 16% longer than average when given low doses of lithium.
At high doses, lithium reduced their lifespan.
"We found low doses not only prolong life but also shield the body from stress and block fat production for flies on a high sugar diet," said co-researcher Dr Ivana Bjedov from the UCL Cancer Institute.
Claire Bale of the charity Parkinson's UK, which part-funded the study, said: "It's encouraging to see that the researchers have been able to identify a key piece of the ageing puzzle, which one day may allow us to intervene in the ageing process."
"This research has the potential to not only help create a healthier older generation, but also provide significant insights into how we could potentially treat or even prevent conditions of ageing like Parkinson's."
Lithium salts have been used in the past as a health tonic and to heal conditions such as gout and migraines.
In modern medicine, lithium is used to encourage mood stability in bipolar disorder and is also being considered for the treatment of memory impairment.
It has a risk of serious side-effects at high doses.


The spending returns of the Stronger In and Vote Leave campaigns in last year's EU referendum are under investigation, the Electoral Commission has announced.

A total of more than £32m was spent on the campaign - with the Leave side funded by donations totalling £16.4m, outgunning the Remain side's £15.1m.
The spending returns show that the Brexit battle was the most expensive referendum ever fought in British political history, said the watchdog.
Lib Dem spending is also under review.
The watchdog said invoices and receipts submitted by the two umbrella Leave and Remain campaigns appeared to be incomplete and they were seeking further details in relation to certain payments.
While this was disappointing, it stressed that it was too early to say whether any offences had been committed.
"Missing spending details undermine transparency and makes the returns harder for the public to understand," said Bob Posner, its director of political finance.
"Where it appears campaigners have not fulfilled their legal obligations, we have begun and will continue to take action to deal with this."
The watchdog has published details of all campaign spending in excess of £250,000 during last year's referendum battle.
The figures show the rival Leave and Remain campaigns secured the majority of their funding through large donations of more than £7,500 each.
The Electoral Commission has also launched a formal investigation into apparently missing documentation from the Lib Dems and late returns submitted by businessman Peter Harris, who campaigned against EU membership.
It has also said it is examining possible discrepancies in paperwork submitted by the European Movement, Labour Leave, UKIP and Conservatives In.


Researchers have decoded ancient recordings from fragments of an asteroid dating back billions of years to the start of the Solar System.

They found tiny "space magnets" in meteorites which retain a memory of the birth and death of the asteroid's core.
Like the data recorded on the surface of a computer hard drive, the magnetic signals written in the space rock reveal how Earth's own metallic core and magnetic field may one day die.
The work appears in Nature journal.
Using a giant X-ray microscope, called a synchrotron, the team was able to read the signals that formed more than four-and-a-half billion years ago, soon after the birth of the Solar System.
The meteorites are pieces of a parent asteroid that originally came from asteroid belt, between Mars and Jupiter.
They represents the left-over fragments of a planet that failed to form. The magnetic recording within it traps a signal of the precise moments when an iron-rich core formed in the asteroid as well as when it froze, killing its magnetic field.
The new picture of metallic core solidification in the asteroid provide clues about the magnetic field and iron-rich core of Earth.
"Ideas about how the Earth's core evolved through [our planet's] history are really changing at the moment," lead researcher Dr Richard Harrison, from the University of Cambridge, told BBC News.
"We believe that Earth's magnetic field is linked to core solidification. Earth's solid inner core may have started to form at very interesting time in terms of the evolution of life on Earth.
"By studying an asteroid we get to see this in fast forward. We can see the start of core solidification in the magnetic records as well as its end, and start to think about how these processes work on Earth."
The meteorites studied by the team originally fell to Earth in Argentina, and are composed of gem-quality crystals enclosed in a metallic matrix of iron and nickel.
Tiny particles, smaller than one thousandth the width of a human hair, trapped within the metal have retained the magnetic signature of the parent asteroid from its birth in the early Solar System.
"We're taking ancient magnetic field measurements in nano-scale materials to the highest ever resolution in order to piece together the magnetic history of asteroids - it's like a cosmic archaeological mission," said Dr James Bryson, the paper's lead author.
"Since asteroids are much smaller than Earth, they cooled much more quickly, so these processes occur on a  shorter timescales, enabling us to study the whole process of core solidification."
Prof Wyn William, from the University of Edinburgh, who was not involved in the study, commented: "To be able to get a time stamp on these recordings, to get a cooling rate and the time of solidification, is fantastic. It's a very nice piece of work."
The key to the long-lived stability of the recording is the atomic-scale structure of the iron-nickel particles that grew slowly in the asteroid core and survived in the meteorites.
Scientists have attempted to synthesise the same iron-nickel structures in the lab, without widespread success so far. But their remarkable magnetic properties rival those of rare earth magnets, a key component of wind turbines and electric cars.
They may yet prove a route to making cheap, strong magnets without the need for scarce rare earth metals.
Making a final comment on the results, Dr Harrison said: "In our meteorites we've been able to capture both the beginning and end of core freezing, which will help us understand how these processes affected the Earth in the past and provide a possible glimpse of what might happen in the future."
The Earth's magnetic field will likely die off when the core completely freezes, and Earth will no longer be protected from the Sun's radiation.
"There's no need to panic" said Dr Harrison. "The core won't completely freeze for billions of years, and chances are, the Sun will get us first."


Otto the bulldog just became a world record breaker after skateboarding through a human tunnel.

But he's the latest in a long line of amazing animal record breakers - Newsround's got your top five.
Jiff smashed the world record for being the fastest dog on two paws.
He took just under 8 seconds to cover five metres on his front paws and was even quicker on his hinds legs, completing the same distance in less than 7 seconds.
Chris the sheep set a Guinness World Record for having the most wool shaved in a single sitting.
Chris' coat was dangerously big and he needed a life-saving shave.
Five shearers volunteered to help and together the team removed 41.1 kilograms of wool.
Chris is now well and has found a new home on a farm.
A French sheepdog called Norman became the fastest canine to travel 30 metres on a scooter.
The three-year-old covered the distance in twenty one seconds - nine seconds under the previous world record.
This hairy cat called Colonel Meow broke the record for having the longest fur.
The Colonel is a Himalayan-Persian cross and at its longest his fur reaches 22.97cm (that's nearly the length of a school ruler).
They're not strictly animal record breakers, but this record wouldn't have been possible without cows and their poo!
This bus powered by cow poo set a new land speed record for a bus after reaching speeds of almost 77mph.


A British company has announced its intention to launch a big constellation of Earth observation satellites.

A prototype spacecraft will go up later this year for testing, with the expectation that a further five platforms will follow in 2019.
Earth-i, based in Guildford, says its train of satellites will deliver rapid, high-resolution imagery of the planet in still and video formats.
At best resolution, these products will see features just under a metre across.
The video is promised in full colour. It could be used to track moving objects such as cars and other vehicles; or, if the scene is held fixed on a specific point, it would enable 3D models of the ground to be constructed.
Earth-i is already well established in the analytics business, processing and selling space pictures to a strong customer base. But this move, announced on the opening day of the biennial UK space conference in Manchester, would see the company operate its own satellites as well.
These platforms are the fruit of an R&D project coming out of Surrey Satellite Technology Limited (SSTL), also in Guildford.
The manufacturer has developed a new class of Earth observation spacecraft codenamed Carbonite.
The first in this series was built in just six months and was launched in 2015. The lessons learned from that experience were then applied to a second satellite which is now set to be the pathfinder in the Earth-i constellation.
"We worked on Carbonite-1 with SSTL and studied the performance to help develop the technology for Carbonite-2 which we will be calling EiX2," explained Richard Blain, the CEO of Earth-i.
"As for the constellation, we will launch that in batches of five. And in terms of the architecture, our baseline plan is for the first batch to go into one orbital plane, and then for the following batches to go into different planes, so that not only do we get high-frequency revisit to places on Earth but we also get to see places at different times of the day."
The total number of satellites in the constellation will depend on how the business for the pictures grows.
Earth-i is chasing a burgeoning market that is attracting new types of customers who are only now beginning to understand the potential of daily, fast-turn-around imagery.
So, for example, whereas governments have long made use of Earth observation (EO) data for mapping towns and cities, to plan major infrastructure ventures and to track land-use changes - the likes of the financial sector is really just beginning to appreciate the intelligence value of space pictures.
Those who trade in commodities are now gaining insights on supply chains, and on the activities at particular factories, ports, mines and oil fields; activities that all have financial implications.
And just as satellite-navigation data - knowing where things are positioned in the world - has become a mainstay of the smartphone applications revolution, there is a feeling that the exploitation of EO data in this domain has barely scratched the surface.
This was part of the motivation for the UK government last year committing more money than any other member state to the Earth observation programme of the European Space Agency (Esa). There are big economic opportunities coming.
"There is an almost insatiable demand for data from space as people are realising its true value to both their planning and daily operations," said Josef Aschbacher, director of Earth observation at the European Space Agency.
"Higher resolution image data from commercial organisations is likely to be very valuable either in its own right or when used in conjunction with other data sources including medium-resolution image data such as that provided under the European Copernicus Programme."
Earth-i's constellation would be the first European system to provide HD video of activity on the ground.
Two North American companies have already started doing this - Urthecast of Canada, and US firm Terra Bella (recently acquired by Planet Labs).
Earth-i currently exploits the imagery coming from SSTL's DMC3 satellites. The capacity on this trio of spacecraft, which take 1m resolution pictures, is wholly leased by a Chinese concern called 21AT. Earth-i is the Beijing companyâ€™s international distributor.
Richard Blain would not discuss the detail of the financing of the new constellation but said that a number of contracts were in place with SSTL.
"We are a well funded private company with a clear financial roadmap, supported by world class professional advisers and with a number of financial instruments at our disposal in order to ensure the continued successful deployment of our constellation following on from the next prototype satellite due for launch later this year," he told BBC News.
Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos


Ulster recovered from conceding an early Logovi'i Mulipola try to beat Leicester in their opening Heineken Cup match at Ravenhill.

Prop Mulipola got over in the corner and skipper Toby Flood converted to give the English club a 7-0 lead.
Winger Tommy Bowe gathered Paddy Jackson's cross-field kick for the try that drew Ulster level on 15 minutes.
Fly-half Jackson kicked five penalties as well as the conversion for a match tally of 17 points.
Leicester were always in contention and secured a losing bonus point when replacement Owen Williams landed a penalty with the last score of the night.
The Tigers have now lost all three European matches they have played at Ravenhill.
But they made a good start when Mulipola touched down in the right corner after a neat break by Flood, who also added the excellent conversion.
Ulster struck back when Jackson delivered a marvellous cross-kick which Bowe superbly took ahead of Niall Morris.
Jackson then calmly converted from the left wing and the sides were level, but not for long as Flood then landed his first penalty after Ulster went in at the side on a Tigers's line-out maul.
Jackson restored parity after Julian Salvi was penalised at the breakdown, then just before half-time a break from home scrum-half Paul Marshall led to Leicester conceding on their own line and Jackson gave the home side a 13-10 half-time lead.
Flood brought the Tigers level again after Jackson had been judged offside - and then Ulster had a Darren Cave try ruled out by the TMO for a forward pass in the build-up.
Leicester were not helped by the 58th-minute sin-binning of Jordan Crane for interfering with substitute Ruan Pienaar - with Jackson kicking three penalties while the number eight was off the pitch to put Ulster 22-13 up.
With the visitors now out of bonus-point territory, and with skipper Flood substituted, they needed to score next and replacement fly-half Owen Williams kicked the last penalty to make it 22-16.
Ulster now face a daunting trip to in-form Montpellier on 19 October, a day after Leicester host Treviso in Pool Five.
Ulster coach Mark Anscombe:
"They might be happy with a point but our objective was to get four points and we achieved that. Each game we play that is our objective and if we stick to doing that we'll come through.
"We're happy with the four [points]. There are only six games and you have to win your home games and we have won our first one. We'll enjoy that and then we'll start to think about our trip to France [to face Montpellier] next Saturday."
Leicester assistant coach Paul Burke:
"Any point at Ravenhill we're really pleased with - it is a difficult place to play.
Media playback is not supported on this device
"Previous years have proven if you don't win your away games you need to pick up a bonus and we did that. It is probably what we deserved out of the game after going nine points down.
"The resolve and the character we showed to get ourselves back - and for Owen to kick that penalty to get us that bonus point - was an outstanding effort from everyone."
Ulster: Payne, Trimble, Cave, L. Marshall, Bowe, Jackson, P Marshall, Court, Best, Fitzpatrick, Muller, Tuohy, Wilson, Henry, Williams.
Replacements: Olding for L Marshall (51), Allen for Bowe (72), Pienaar for P Marshall (46), Lutton for Fitzpatrick (76), Diack for Muller (65).
Not used: Herring, Black, Henderson.
Leicester: Morris, Benjamin, Goneva, Bowden, Thompstone, Flood, B Youngs, Mulipola, T. Youngs, Cole, Deacon, Parling, Slater, Salvi, Crane.
Replacements: Hepetema for Benjamin (75), Williams for Flood (72), Mele for B Youngs (64), Briggs for T Youngs (72), Kitchener for Deacon (59).
Not used: Stankovich, Balmain, Waldrom.
Referee: Romain Poite (France).
Att: 14,000.


A self-confessed pornography addict who admitted possessing and distributing child abuse images has been given a community sentence.

Damien Bancroft shared the photographs and videos from addresses in Dundee and Forfar over a four-and-a-half year period.
A court was told that the 36-year-old could not explain why he had distributed the material to others.
Bancroft had already been placed on the sex offenders register.
Depute fiscal Trina Sinclair previously told Forfar Sheriff Court court that police officers, acting on information, found more than 600 still images and 16 videos on two laptops and also on a mobile phone.
Miss Sinclair said Bancroft admitted to police that he was a pornography addict, having started watching adult material at the age of 19.
He accepted that he had downloaded and shared images with others but could not explain why that included indecent images of children.
Bancroft admitted taking or making indecent photographs or pseudo-photographs of children between 14 May, 2011 and 20 October, 2015.
He further admitted distributing indecent photographs of children or pseudo-photographs - where computer graphics have been used to generate a photograph-like image.
Defence solicitor Brian Bell said: "He knows this is a serious matter and he has taken action to seek immediate assistance.
"He has issues he needs to address."
Sheriff Gregor Murray imposed a three year community payback order with supervision, 225 hours unpaid work, a requirement to take part in a sex offender group work programme and restrictions on his internet use.
He said: "The distribution element is a serious aggravation. The consequences are obvious."


Derbyshire and Leicestershire both took 11 points after a flat pitch and huge first-innings totals resulted in a draw in County Championship Division Two.

In reply to Leicestershire's 619, the hosts' Billy Godleman and Shiv Thakor responded with hundreds on day three.
Derbyshire added just one run to their overnight second-innings total to post 533, before Harry Dearden made 78 as the Foxes declared on 217-3.
That left Derbyshire 303 to chase, but a draw was agreed after just 10 overs.
The hosts began the fourth day on 532-8, but Clint McKay (3-78) dismissed Rob Hemmings and Zak Chappell (4-108) had Tony Palladino caught behind to end the innings swiftly.
Dearden and Paul Horton (56) then put on an opening stand of 125 to help set up a declaration, but after Derbyshire openers Ben Slater (28 not out) and Billy Godleman reached 42-0, the captains shook hands for a draw.
Neither side has won a Championship match in 2017.


Belfast Giants suffered a shootout defeat in Friday night's Elite League clash against Nottingham Panthers.

Jeff Brown put the hosts ahead at the National Ice Centre before Colin Shields levelled at 12:14.
Ollie Betteridge restored Nottingham's lead six minutes later but Blair Riley hit back with a third-period equaliser for the Giants.
Overtime failed to separate the teams and Matt Carter converted in the shootout to win it for Nottingham.
Belfast missed the chance to go second in the standings and they are back in league action on Saturday night with an away game at Manchester Storm.


Awtaad, ridden by Chris Hayes, beat favourite Galileo Gold to win the Irish 2000 Guineas at the Curragh.

The 9-2 shot kicked for the finish line with two furlongs remaining to beat the Newmarket Guineas winner by two and a half lengths with Blue De Vega third.
It was a second victory in the colts' classic for trainer Kevin Prendergast, who last won the race 40 years ago with Northern Treasure.
"I'd say he's as good a horse as I've had," said Prendergast, 83.
"But how far he will go I don't know. He was forced to go a bit early today as Frankie Dettori (Galileo Gold's jockey) was in a bit of bother on the inside, so he kicked and hoped for the best.
"I don't know where he will go next. The boss man (Sheikh Hamdan) makes the decision and we go along with it.
"He's in the Derby and the Irish Derby, so we'll see what he wants to do."
Galileo Gold, trained by Hugo Palmer, was looking to become the ninth horse in history to win both the Irish and English 2000 Guineas.
Detorri rode Galileo Gold to a surprise victory in the first classic of the 2016 Flat season, the 2000 Guineas at Newmarket on 30 April.
It gave Palmer his first victory in the race and saw the Irish and English double completed in successive years following the success of Gleneagles in 2015.


Newport County have abandoned their attempts to sign free agent Reuben Reid.

The former Plymouth striker has been in talks with County manager Warren Feeney for a number of weeks after he rejected Argyle's contract offer in the summer.
"That deal is probably dead now, we have spoken to him, but I think I am probably going to leave that one now. It is gone," Feeney told BBC Wales.
"I won't be waiting around, so we can probably put that one to bed now."
He continued: "He is a great fella - but I want players who are ready to come in and play.
"I am sure he'll sign somewhere. I have plenty of strikers but would have taken one more, you can't have too many strikers, I honestly believe that."
Feeney added three players to his squad before the transfer window closed on 31 August.
Newcastle United defender Kyle Cameron, Cardiff City forward Rhys Healey and Queens Park Rangers forward Reece Grego-Cox have joined on loan until January.


As many as 70 deposit boxes were opened during a raid in London's jewellery quarter, police have said.

Burglars gained entry to Hatton Garden Safe Deposit over the Easter weekend. Scotland Yard was alerted on Tuesday.
Officers said a "slow and painstaking process" of forensically examining the scene was under way.
Ex-Flying Squad chief Roy Ramm has said he "would not be surprised" if the jewellery stolen during the raid was worth as much as £200m.
The Met, which has not yet commented on the worth of the jewellery stolen, said it was "photographing the scene and recovering exhibits in meticulous detail".
It said the burglars used heavy equipment to break into a vault used mainly by jewellers and gold dealers.
A spokesman said: "Officers are working closely with Hatton Garden Safe Deposit Ltd to establish the identities of those affected.
"Police will be contacting victims directly as and when they are identified."
BBC News correspondent Daniel Sandford said: "There is still a concern that the thieves may have had some kind of inside knowledge. For example, the brand new alarm system which had just been fitted in the building had not yet been switched on."
Michael Miller, a jeweller from Knightsbridge, said he "felt sick" at the prospect of losing up to £50,000 of uninsured jewellery and watches.
He said a £5,000 watch he bought for his son might have been stolen and he felt "dismay, shock and disbelief" when he heard the news.
Gem industry expert James Riley said most businesses storing items would be insured but individuals may not.
"If you can't afford your jewellery insurance you put it in a safety deposit box which is going to cost you between £300 to £400 a year and you know it is the most secure place you can put it as your insurance company would be very happy with you putting it there," he said.
Ex-Flying Squad chief Mr Ramm told BBC Radio 4's Today programme: "There's a sort of old-fashioned audacity about it.
"The amount of money and the goods that are taken is never fully revealed... and there's a good chance that not everybody would declare.
"I would not be surprised, given where this one is in Hatton Garden, if £200m is about the amount stolen."
Norman Bean, who had a diamond ring and bracelets stored at Hatton Garden Safe Deposit, said he was told the burglars accessed the vault via a lift shaft.
"They went down the lift shaft, made a big hole in the wall, got into the safe deposit and I think they drilled into the boxes.
"They could have been there all weekend, who knows? It's a disgrace, it's like something out of a film," added Mr Bean.
Neil Duttson, a diamond dealer, said tracing any gems stolen in the heist would be nearly impossible.
"Once diamonds have been re-cut and polished there is no geological map," he said.
"I imagine they will be sat on for six months. You can expect some cheap diamonds will be coming on the market soon."


Sainsbury's has reported a fall in underlying sales, with the UK's second-largest grocer warning the market remains "challenging".

Like-for-like retail sales - excluding fuel - were down 0.8% in the 12 weeks to 4 June as food price deflation continued to grip the sector.
In the previous quarter, sales had risen for the first time in two years.
Chief executive Mike Coupe said price pressures meant "the market will remain competitive".
But Mr Coupe said he expected the supermarket "to continue to outperform our major peers".
Total group sales rose 0.3% for the three months, with an "encouraging performance" from the bank.
Earlier this year, Sainsbury's agreed a Â£1.4bn takeover of Argos-owner Home Retail Group, although last month the Competition and Markets Authority said it would examine the deal to see if it would lead to "a substantial lessening of competition" for consumers.
The UK's big four supermarkets have been engaged in a price war as German discounters Aldi and Lidl expand rapidly in the UK.
Sainsbury's strategy has been to invest in improvements in stores and cut prices on everyday products rather than run promotions. During the three months Sainsbury's ended its Brand Match campaign.
Mr Coupe said: "Market conditions remain challenging. Food price deflation continues to impact our sales and pressures on pricing mean the market will remain competitive for the foreseeable future.
"However, we are confident that our strategy to be a trusted multi-channel, multi-product and services retailer is delivering and will enable us to continue to outperform our major peers," he said.
The retailer has also re-introduced sales of vinyl records, after a break of 25 years, and now claims to be the biggest seller of vinyl on the High Street with an 8% market share.
Sainsbury's has reported two straight years of profit decline and its shares have fallen 7% over the past month.
In May, it said underlying profits for the year to 12 March fell to Â£587m from Â£681m in the previous year.
Sainsbury's shares opened more than 2% higher on Wednesday, making it the biggest riser on the FTSE 100.
Laith Khalaf, senior analyst at Hargreaves Lansdown, said: "Of late there have been some tentative signs that the worst might be over, with transaction volumes rising, but falling food prices continue to keep like-for-like sales in negative territory.
"Nothing will move the dial at Sainsbury more than the planned acquisition of Home Retail Group, the parent company of Argos. If the takeover proceeds, integration goes smoothly, and performance is improved, the deal will look a triumph.
"But like Sainsbury, Argos has its own problems, and the outcome of two challenged businesses joining forces still remains very uncertain," he said.


A private ambulance provider has apologised for delays after missing targets for three years running.

Arriva Transport Solutions, which carries non-emergency patients in Leicestershire and Rutland, was fined nearly £45,000 last month.
The family of a man who was left waiting nine hours for a hospital transfer after a stroke said it should not be allowed to renew its contract.
The local NHS group said most patients were happy with the service.
Arriva boss Paul Willetts said "it was not good enough" and apologised for missing targets for getting patients to and from hospitals on time, which he said was partly down to increased demand.
He also apologised to the family of Michael Burden, 76, but his daughter Emma Purcell said the company should not be "rewarded" by having its contract renewed.
"When they're consistently letting people down, why would they get the contract again?" she said.
West Leicestershire Clinical Commissioning Group, which manages the contract, has fined Arriva in each of the three years its contract has been running.
The group's chief executive Toby Sanders said 88% of patients would recommend the service to family and friends.
"We don't always get it right and Arriva have recognised that... We have used fines as part of our contract but actually it's not the fines that improve outcomes for patients," he said.
"What we've been focusing on is improving the service, improving the response times and also making sure we've got the right connections with the other parts of the service."
He said there were 18 months left on the contract and it "would be a poor use of public money" to terminate the agreement before then.


There are close-up images, and then there are the ones taken by Muhammad Roem, an amateur Indonesian photographer.
From dancing frogs to cheeky geckos, there is little that escapes 28-year-old Mr Roem's camera.
The full-time nurse started photography only three years ago as a part time hobby.
Now the Batam-based photographer spends whatever free time he has chasing down his subjects in the wild.
"I follow the insects in order to capture exact expressions. Sometimes from more than a dozen photos there will only be one photo with a good expression. Other days I don't get anything," he tells the BBC.
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Many people don't know or see much into specific parts of an animal," Mr Roem says. "I try to showcase one specific part, for example if you look at their eyes- it's awesome."
"I first started learning photography by myself, then later started getting feedback from a teacher," Mr Roem says. "I mostly go around Batam taking photos, but when I have free time I try to travel around Indonesia."
His busy work life means he has little time to take photographs, but when he does he spends up to a week editing a single shot.
"I take around one full day to take one photograph," he says. "But up to a week to finish the photograph, including editing and processing."


Transvestite Vampire Biker Nuns from Outer Space is among the contenders for a prize given annually to the year's oddest book title.

This year's seven-strong shortlist includes Too Naked for the Nazis, Soviet Bus Stops and Reading from Behind: A Cultural History of the Anus.
The winner of the Diagram Prize is decided by public vote.
Previous winners include How to Poo on a Date and Goblin-proofing One's Chicken Coop.
Reading the Liver: Papyrological Texts on Ancient Greek Extispicy, Paper Folding with Children and Behind the Binoculars: Interviews with Acclaimed Birdwatchers complete this year's line-up.
All the titles were nominated by industry insiders and members of the public - aside from Too Naked for the Nazis, which was put forward by its author.
"Transvestite Vampire Biker Nuns from Outer Space is not only a trenchant examination of cult film, but would be an excellent theme for your next fancy dress party," commented The Bookseller's diarist Horace Bent, dubbed 'the custodian of the prestigious Diagram Prize'.
The prize, now in its 38th year, was originally conceived in 1978 by Trevor Bounford and Bruce Robertson of The Diagram Group as a way to alleviate boredom at Frankfurt's annual book fair.
It was first awarded to Proceedings of the Second International Workshop on Nude Mice. Two years - 1987 and 1991 - had no award due to the lack of odd titles.
The Bookseller has hosted the prize since 1982 and invites members of the public to vote for their favourite title on its website.


A man has been arrested on suspicion of making death threats to Labour Party leadership contender Angela Eagle.

The 44-year-old was arrested in Paisley, Renfrewshire after allegedly making threats to kill the Wallasey MP in an email, Merseyside Police said.
In a separate incident a brick was thrown through a window of her Wirral constituency office which police are also investigating.
Ms Eagle, 55, is currently campaigning to replace party leader Jeremy Corbyn.


A union is holding a vote on strike action in a row over 141 job losses at the Hull College Group.

Julie Kelley from the University and College Union (UCU) said 60 lecturers and other staff would be made redundant.
She claimed the cuts would "diminish the student experience".
The college, with sites in Hull, Harrogate and Goole, said it was operating in a "challenging financial climate".
More on this and other Hull and East Yorkshire stories
The UCU said as well as the cuts to the number of lecturers the college would close its three children's nurseries, making 37 staff redundant.
The other losses would come from management, library and IT staff. The union said that 385 jobs had been lost at the college since 2011.
"This is an outrageous attack on hardworking and dedicated staff," said Ms Kelley.
"There is a lot of anger amongst staff who believe the college management is rushing into yet more job losses without fully considering alternative options."
Hull College Group said demographic factors had impacted on the number of 16-18 year olds in its catchment area.
The proposal to close the subsidised nurseries in 2016 had been taken due to the financial losses incurred, it said.


A group of fundraisers has begun an attempt to swim the River Thames restricting themselves to doggy paddle.

The 10 swimmers set off from Lechlade, Gloucestershire aiming to complete the 155 mile (150km) route to Putney.
Hamish Reid said doggy paddle was the "perfect stroke" for river swimming. He added the biggest challenge would come in the tidal section of the Thames.
The team has so far raised almost Â£10,000 for the UK Stem Cell Foundation charity.
The relay swimmers are accompanied on the river by paddle boarder and a giant inflatable pink dog mascot during the six-day challenge.
Mr Reid said: "There are some strengths of the stroke - you keep your head out of the water, we're trying not to ingest too much of the Thames.
"It's good for chatting - with your head up you can chat to boaters and people on the sides."
He said he came up with the idea to raise money for stem cell research into spinal injuries after a friend was paralysed in a swimming accident.
It is hoped they will complete the challenge in Putney on 27 August.


A coroner has reopened the inquests into the deaths 21 people killed in the Birmingham pub bombings more than 40 years ago.

Many of the families regard the inquests as their last chance to find out exactly what happened on the night of 21 November, 1974.
Six men were convicted and then acquitted of the atrocity and no-one has since been convicted of involvement in the bombing, which is widely attributed to the IRA.
The role of a coroner is to determine who the deceased was and how, when and where they died. If they feel they need further investigation, an inquest is held.
Inquests were therefore opened into the 21 victims but adjourned to allow for a criminal investigation. Because that investigation resulted in a conviction, it was concluded the questions about the deaths had been answered by the trial.
However, when the convictions of the Birmingham Six were quashed in 1991, the inquests remained closed.
Julie Hambleton, whose 18-year-old sister Maxine died in the attacks, said: "The lives of 20 families changed on that night and they have never been told the truth about what happened.
"There are many more - the casualties and those who came to their aid on the night - whose lives were changed forever, too".
The move to reopen the inquests follows a campaign by the Justice 4 the 21 campaign group, led by family members of victims of the bombings.
They met Home Secretary Theresa May and Northern Ireland Secretary Theresa Villiers in March 2015 to lobby for an inquest. An application for a fresh inquest was also lodged with the attorney general.
Relatives of Maxine Hambleton, Trevor Thrupp and James Craig made an application to Louise Hunt, the senior coroner for Birmingham and Solihull, for the hearings to resume.
Human rights lawyer Kevin Winters, who has represented families of victims of the Troubles in Northern Ireland, said he believed there was a basis for an inquest, which would provide families with access to certain "disclosure materials" he claimed had been kept from them.
This could be the last chance, in their lifetimes, for campaigners to have evidence heard in public which was not available in 1974.
They hope Ms Hunt will call key witnesses, who the families believe can identify the bombers.
Ms Hambleton said: "All we want is one thing - justice. No more, no less. We don't want money, we don't want an apology. All we want is justice."
On the evening of 21 November 1974, hundreds of people, many who were young and out with friends, family and work colleagues, were inside two busy Birmingham city centre pubs.
Meanwhile, a man telephoned the Birmingham Post and Mail newspaper to warn two bombs had been planted in the city centre. Officers in Birmingham, which had seen a spate of IRA bombings during the mainland campaign, rushed to the scene, but were too late.
At 20:17 GMT a bomb exploded in a duffel bag in the Mulberry Bush pub at the base of the city's iconic Rotunda building, killing 10 people. Ten minutes later, a second bomb went off in the Tavern in the Town, leaving 11 more dead.
A total of 182 people were also injured in what was, at the time, the worst terrorist atrocity on English soil.
The 21 people killed - seven women and 14 men - were aged between 17 and 51. Thirteen of the victims were under 30, including five in their teens.
Over the decades, stories have emerged of those who died and some of the people seriously injured have spoken of their experience and the lasting affect it had on them.
Ms Hambleton, who has led calls for a public inquiry into the attacks, recalled how her "world fell apart" aged 11 when her 18-year-old sister Maxine - who she described as being "like another mother" - was killed while handing out party invitations in a pub.
Six men were wrongly convicted of the two pub bombings but were finally released in 1991. During the near 17 years they spent behind bars the case of "The Birmingham Six" became known as one of the worst miscarriages of justice seen in the UK.
The IRA is believed to have carried out the bombings, although no-one has ever admitted responsibility.
However, no-one has ever been brought to justice for the 21 murders.
West Midlands Police began re-investigating the case in 1991 and officers generated 5,000 documents, statements and reports. But in 1994, the force said there was insufficient evidence for any prosecutions.


Ospreys fly-half Dan Biggar has become the first player in Welsh regional rugby to pass 2,000 points.

The 27-year-old kicked 14 points during Ospreys' 19-9 Pro12 win over Scarlets on Tuesday.
Biggar has now registered 2,001 points from 195 games since making his Ospreys debut in 2008.
"There's definitely no luck in and around that. Everything around him is geared to winning games," head coach Steve Tandy said.
Biggar, who has 51 caps for Wales, kicked four penalties against Scarlets as Ospreys secured their 11th consecutive home victory in all competitions.
Tandy said Biggar had "stepped up" to the challenge laid down by fellow fly-half Sam Davies, who has been selected over him for much of the 2016-17 season.
"It's pretty remarkable, but it's not a real surprise when you look at how much time he spends on the training field," Tandy said.
"It's a pretty special effort and he's still got a lot of rugby left in him."
Scarlets led Ospreys 9-6 at the break but Tandy said his side deserved to win after the visitors had three players sin-binned.
Prop Rob Evans was cited in the first half for a high tackle, before flanker Will Boyde and wing Steffan Evans were dismissed for illegally killing mauls in the second.
"There's enough confidence, there wasn't a lot of stress going through the team," said Tandy.
"It was calm, measured and I think we thoroughly deserved the win."
Head coach Wayne Pivac said he had "no complaints" over the decisions that went against his side.
"You could see them coming," said the New Zealander.
"We're not pointing the finger at the referee. We need to look at our own performance."
Flanker Boyde conceded a penalty in the second half to give Ospreys the lead, but Pivac praised his impact on the game.
"He had a very good game, but he'll be remembered for the yellow card probably and that's a learning for any player," he added.
"His entry was fine, but it was just the fact he brought the maul down and I'd rather they score out wide than score under the posts.
"I thought he had an exceptional game outside of that incident."


London DJs The Bush Twist shot a music video of their track Friday Night around Ghana.

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16 December 2014 Last updated at 18:06 GMT
With a rented boom box the pair took to the streets, filming passers-by in Accra, school children in Akim and the landscapes of the Kwame Nkrumah Memorial Park.
"People were just so excited and happy. When people hear music and a beat they want to dance. You don't have to ask. They will just come and dance and jump in front of your camera," says Ollie Williams, one of The Busy Twist duo.
Inspired by highlife, reggae and dance sounds emanating from Ghana's streets and clubs, the track represents something different from digitally driven dance music.


BBC's Middle East Bureau Editor Paul Danahar reflects on six months of covering the Libyan uprising from both sides of the conflict, using pictures of some of his more memorable moments.

For a man supposedly worth millions, you would not know it by his boots. When the BBC interviewed Col Gaddafi in March, I was expecting the meeting to take place at a secret desert pavilion. Instead it was a seaside restaurant in central Tripoli. His eyes were hidden behind gold Cartier sunglasses. His flowing brown robes gave off the light scent of sandalwood. "I don't like money," he said. "I have a tent". One look at his black cowboy boots and you would think he was telling the truth. The soles were cracked and pitted, the heels worn. Last week, when I walked around his Bab al-Aziziya compound on the day it fell, I saw where the money had gone. He had a tent like no other tent in the world. But by the end of the day it was just ashes.
The next image shows the last big demonstration in the Tripoli area of Tajoura before the authorities cracked down with pre-dawn raids and mass arrests. It was just after prayers one Friday in March. I went back the following week when the BBC team broke away from their government minders at the Rixos Hotel. There was no demonstration. The anti-Gaddafi graffiti had been painted over and the local imam told us many young people had been taken away during the night. Soon after we turned up, government heavies arrived in minivans to take us away. This was the last time journalists were able to move easily around the capital before it fell five months later.
The next audience with Col Gaddafi was on 2 March, the anniversary of the "establishment of the people's authority". This is when Col Gaddafi says he handed over all power to the people, so he could not technically stand down. The crowd was delighted, the rest of us bemused because he arrived in a brand new golf buggy, its front seat draped with a white sheepskin rug. He talked for three hours. Occasionally he allowed some chants and cheers, and then tapped his microphone, at which the crowd promptly shut up. The last time I saw Col Gaddafi, he was driving his buggy towards a lamp post. But his security team cleared a path and he drove off with two secret service types clinging to the back.
This was one of the government soldiers who had taken back the town of Zawiya, near Tripoli, from the rebels. The fighting was brutal as was the treatment of those arrested by the authorities. Some BBC colleagues were detained for 24 hours and subjected to mock executions. When journalists did get in, it was by media bus under strict supervision of the authorities, but the green-and-white bunting could not hide the scale of the destruction. The makeshift cemetery in the town square, where the rebels had buried their fallen fighters, had been bulldozed. The rebels winning it back proved to be a turning point in the war.
The man below was typical of the rebel fighters on the eastern front outside Ajdabiya in April. They were mostly disorganised and ill-disciplined. He was among those who fled at the first sign of an incoming round. It was at this time that the Libyan government was trying to push the idea that these fighters were linked to al-Qaeda. We tended to see them as more of a danger to themselves than to us. Their evolution into a proper fighting force took many months and some training from foreign military experts. Combined with a steady stream of new weapons and Nato's air campaign, over time they became a force to be reckoned with.
Years of being silenced have led to an explosion of graffiti in Libyan towns and cities. Artists played a cat-and-mouse game with the authorities in Tripoli - they sprayed by night and government lackeys whitewashed by day. This wall - in Liberation Square in Misrata - is in no danger of being repainted. Less artistic but more poignant was graffiti by the family of Abdel Salem Fouzy Alshaba, a 23-year-old economics student. The day after I took this picture, I watched him die at a hospital on the city's western front line. He sustained head and back injuries from a grad rocket fired by Gaddafi forces. Within days, his family was using a spray can to rename streets across the city in his honour.
This building in the Bab al-Aziziya compound is where Col Gaddafi made most of his anti-Western speeches. It was bombed in 1986 by US warplanes in revenge for a nightclub bombing in Germany that targeted US servicemen. The fist crushing the US fighter jet symbolised Col Gaddafi's defiance. After the compound fell to rebel forces, young men were queuing to have their photo taken on it. A few days later, someone "liberated" the famous fist from its mount and it has not been seen since.
They could not get to the man so they were tearing apart everything he owned. This was inside Gaddafi's compound, where I watched rebels walking away with vases, paintings and fridges. What they could not carry, they smashed to pieces. Comparisons have been drawn with the fall of Baghdad, raising fears of what may follow. But Tripoli is a very different story. Only symbols of the regime have been attacked. The rest of the city has remained largely secure.
This would have got this young boy's family in a lot of trouble a few months ago. But the images people were once forced to mount at their homes and businesses are now used to show their contempt for the regime. This was outside a hospital in Misrata. But everywhere in Tripoli, people are walking over images of the self-styled father of the nation. Libyans have lived with the cult of Gaddafi for more than four decades. No-one knows where he is hiding, but what is clear is that this young Libyan is not going to grow up like his parents - in Col Gaddafi's shadow.


Bond star Ben Whishaw is to star in a Greek tragedy at the Almeida theatre in north London.

The actor, who will reprise his role as Q in the new 007 film Spectre, will play Dionysos in a new version of Euripides' Bakkhai.
The role marks Wishaw's debut at the theatre, known for being more artistically edgy than venues in the heart of the West End.
The play is part of the theatre's 2015 Greek season, announced on Thursday.
"At the Almeida we strive to create theatre that asks questions of its audiences, of who they are and the world they live in, work that is alive and resonant," said creative director Rupert Goold.
"When we came to the writers of Ancient Greece we wanted to be true to their plays - staging them in full complexity, presenting their formal iconoclasm, their humour, musicality, politics, violence and unswerving drama."
The season will run from May to November and other highlights include new versions of Oresteia and Medea as well as talks, readings and events designed to give the public a rounded understanding of the era.
Bakkhai is described by the Almeida as an "electrifying tragedy... a struggle to the death between freedom and restraint, the rational and the irrational, man and god".
The story tells of Pentheus, king of Thebes, who enters into a conflict with Dionysos by banning the wild, ritualistic worship of the god.
A stranger arrives to persuade him to change his mind - but the king cannot escape Dionysos' anger - and, ultimately, his punishment.
Whishaw will bring in the audiences as one of the UK's brightest young talents.
His stage work is already substantial and includes roles in a West End production of Mojo by Jez Butterworth; His Dark Materials and The Seagull, both at the National Theatre; and Hamlet at the Old Vic.
On the big screen, Whishaw first took on the role of 007's gadget designer Q for 2012's Skyfall.
He most recently voiced the CGI character of Paddington in 2014's big screen hit of the same name.
His other films include Enduring Love, Layer Cake, Perfume, Stoned, I'm Not There, Brideshead Revisited, Bright Star, The Tempest, Cloud Atlas and Lilting.
Later this year, he will appear opposite Colin Firth and Rachel Weisz in The Lobster  and alongside Meryl Streep and Helena Bonham Carter in Suffragette.
Whishaw won a TV Bafta for the BBC adaptation of Richard II. He's also had TV roles in The Hour, Nathan Barley and Criminal Justice, for which he won best actor awards at the Emmys and the Royal Television Society.


Are you dreaming of a holiday in the Maldives?

You may want to choose another fantasy destination after the British Foreign Office told tourists to be aware that some political demonstrations in the capital, Male, have led to violence. It did add, though, that most trips there are trouble-free.
At the end of last month the Maldives celebrated its birthday, 52 years since independence from Britain.
But the festivities were marred when the government ordered troops to storm the country's parliament and prevent opposition MPs from entering.
It was the latest dramatic attempt by President Abdulla Yameen to maintain his grip on power, and the latest twist in a tale of tropical intrigue worthy of a thriller.
The story is certainly set against a suitably exotic backdrop.
The Maldives is justifiably famous for its breathtakingly beautiful beaches and breathtakingly expensive luxury hotels.
But while the water of the coral reefs that surround them may be crystal clear, politics in the so-called "island paradise" has always been very murky indeed.
The political drama is centred, not on the beaches but on Male, the tiny, urbanised island where all of the Maldives' major institutions are based and which is one of the most densely populated cities on Earth.
For 30 years the country was a corrupt autocracy, ruled with the proverbial "iron fist" by Maumoon Abdul Gayoom.
President Gayoom shrugged off numerous coup attempts during his three decades in power, but the wily tactician could not resist forever the growing demand for democratic reform.
In 2008, a charismatic young progressive, Mohamed Nasheed, swept to power in the country's first democratic elections.
He rolled back repressive laws, bolstered democratic institutions and captured the world's attention with an underwater cabinet meeting to highlight the risks of rising sea levels.
But the Maldives' brief moment as a model Islamic democracy was not to last.
Less than four years later, Mr Nasheed resigned following a mutiny by the police and weeks of demonstrations after the arrest of the chief justice, something he now calls a coup.
In November 2013, Mr Yameen took office, but as he is Mr Gayoom's half-brother, it looked like a return to the old order.
However, over the last year the two strongmen have had a spectacular falling out.
So much so that Mr Gayoom, the grizzled old dictator, has thrown in his lot with the dashing young democrat, Mr Nasheed.
To give you an idea of just how improbable this union is, you should know that Mr Nasheed was imprisoned and tortured during Mr Gayoom's rule.
Nevertheless these unlikely allies have prospered and - bolstered by defections from the ruling party - the opposition has managed to gain a small majority in the Maldivian parliament.
They had a plan - to stage a coup, but a democratic one.
They tabled a no-confidence vote against the speaker of the country's parliament.
The idea was to replace him and his deputy with opposition figures, who would lead an emergency government until elections early next year.
It looked likely to work, until, that is, Mr Yameen literally called in the troops.
They barred opposition MPs from entering parliament for the vote, thereby putting paid to the plotters' plans.
Since then Mr Yameen has been trying to strip the opposition of its majority, arresting MPs and ruling that defectors must resign their seats.
It has been enough to allow him to cling on to power, for the moment at least.
If you are wondering why on earth you should care about this sun-soaked soap opera, you need to see the wider picture - because the Maldives is at the centre of a much bigger strategic power play.
The country's more than 1,000 islands stretch 800km (500 miles) into the Indian Ocean.
They straddle crucial sea-lanes, notably the busy but prosaically named bottleneck, the "One and a Half Degree Channel".
It makes the Maldives a pawn in the great game for regional influence being played out between India and China, the outcome of which may influence the shape of the world economy for years to come.
But there are more basic principles at stake here too - human rights and the rule of democracy.
And they matter just as much in small nations with great beaches like the Maldives, as they do anywhere else in the world.


Nicola Sturgeon has said the situation involving former MP Michelle Thomson was "not easy" for the SNP.

The former Edinburgh West MP resigned the party whip and was eventually deselected amid fraud allegations against a former business associate.
However, she said she was given no choice in the matter and asked for an apology from party leader Ms Sturgeon.
Ms Sturgeon said she appreciated the ex-MP "has had a really tough time", but said it "wasn't easy" for the SNP.
The first minister said it was for the party to discuss Ms Thomson's "future relationship" with the SNP going forward.
Ms Thomson was elected SNP MP for Edinburgh West in the 2015 general election, taking the seat from the Liberal Democrats and immediately being installed as the party's business spokeswoman. However, she resigned the party whip in September that year following allegations about past property dealings.
She was one of five people named in a report sent to prosecutors by Police Scotland more than a year later, but the Crown Office ultimately concluded that there should be "no criminal proceedings at this time" due to an "absence of sufficient credible and reliable evidence".
Ms Thomson always strongly denied any wrongdoing, insisting all deals her business took part in were both legal and fair, but was deselected by the SNP ahead of June's snap general election. The seat was subsequently re-taken by the Lib Dems.
Ms Thomson said she thought Ms Sturgeon may have "panicked" at the time the allegations were first made, as she was "relatively new in her role".
She said she was given "no support" and had "no chance to put across my side of the story", saying she was given no option but to resign the party whip at Westminster.
Deputy First Minister John Swinney has insisted that "the decision to withdraw from the party whip was Michelle's decision", adding that it was "taken as a consequence of conversations with those responsible for conduct matters within the party".
Ms Thomson was also critical of the media's "absolutely unfair" portrayal of the affair, calling for an apology from the BBC for its coverage.
Asked about Ms Thomson's account, Ms Sturgeon said "clearly on some aspects I would take a different view", but said she did not want to go into detail.
She said: "I regret very much that we were confronted with a situation where one of our newly-elected MPs was facing serious allegations - of course I regret that.
"It wasn't a situation of my making, it wasn't a situation clearly I would have chosen to be in. And I appreciate that what followed on that, the investigation that took place, was not easy for Michelle Thomson and it wouldn't have been easy for anyone in that situation.
"But I think people would also appreciate that it wasn't a particularly easy situation for the party to be in either.
"Michelle is now, happily, in the position where she can put this behind her. She has been cleared of any wrongdoing and I am sure she is very relieved about that so we can now look forward and have a discussion directly with her.
"But with the greatest of respect we will have the discussion, if she wants to have it, with her and not through the medium of the BBC."


The BBC's Generation projects are designed to ensure the voices of younger people are heard in BBC programmes and content around elections and political events.

With both a referendum on EU membership and a broad set of elections UK-wide, 2016 is a huge year for democracy.
As such, it is more important than ever that young people step up to be involved in discussions about what direction we should take.
BBC Generation 2016 is focused on elections in Wales, Scotland, and Northern Ireland, to the Northern Ireland Assembly, the Welsh Assembly, and the Scottish Parliament.
All three institutions go back to legislation passed in 1998: the Good Friday Agreement in Northern Ireland, the Government of Wales Act, and the Scotland Act.
Many 18-year-olds voting for the first time in an election in Wales, Scotland or Northern Ireland were born in that year, and have lived almost entirely under devolved government.
BBC Referendum Generation running concurrently, is a broad ranging group of young people, from the whole of the UK and across Europe, who we have brought together to discuss the UK's place in the European Union.
We have voices drawn from a range of diverse backgrounds and communities.
They'll appear across a range of BBC output, discussing the issues above, or talking more broadly about life as a young person today.
The BBC Generations team is delighted to be able to bring these young voices to the heart of UK debate.
Join the conversation with @bbcgen2016 and find out more at bbc.co.uk/generation2016.


One of Britain's few female auteurs is a favourite to win at the Berlin International Film Festival with a comedy about what she describes as "broken England."

The Party is just over an hour long, shot in black and white, and has an all-star cast including Kristin Scott Thomas, Timothy Spall, Cillian Murphy and Patricia Clarkson as a group of politicians and intellectuals whose lives dramatically unravel at a social gathering.
Its writer and director, Sally Potter, describes it as a "political statement, a political comedy".
"Politics affects everything in the film," she says, "right down to the politics of the relationships between the characters."
From an instrumental, clunky-sounding version of the well-known hymn Jerusalem at the start, to Kristin Scott-Thomas's role as a politician on the verge of a cabinet job, and its setting in an affluent part of London, The Party seems culturally timely.
Potter started writing the film before the last general election in 2015, when she "had the sense people were losing the ability to know what truth was in political life".
"That's why truth telling is central to my story, it's the notion that politics is everywhere and the way forward is truth telling."
Potter told a press conference in Berlin that the film was "a light and loving look at the state of England - a broken England - and the sense of what can go wrong when people lose touch with their principles".
Peaky Blinders star, Irish actor Cillian Murphy, recounts that the Brexit vote happened during the two- week shoot for the film.
"It was extraordinary and profound. It brought home to us how insightful the script was and how it spoke to modern Britain - and then what's happened in America since."
"The Brexit vote really threw us," adds Timothy Spall. "There was a massive sense of mourning amongst the cast and crew."
Spall agrees that the film's setting amongst the British "elite", derided by many critics as "out of touch" with public opinion, is significant.
"They're people who have prided themselves on their ability to maintain civilisation, they feel they carry the right side of things. If you want to rule your country you have to maintain an inbred arrogance that eventually starts to fall apart in the film.
"There's a switch from being articulate to seeing the animal in us. It's a very physical comedy in that sense."
Murphy, who plays a drug-taking, firearm-carrying, city banker, said that he loved the idea of "finding humanity in a banker - even if they aren't society's favourite people at the moment.
"I just liked the way the character unravels in front of our eyes - and perhaps that provokes some pathos."
Sally Potter, who has a background in performance art, has made seven feature films in her career since her first short film, Jerk, made in 1969.
The highlight so far may be her adaptation of the Virginia Woolf novel Orlando. Made in 1992, and starring Tilda Swinton as a character who moves through seven centuries as both a man and a woman, it received global critical acclaim.
This time, she says, she wanted to make a comedy with a lot of language building on the cinematic tradition that stretches back to theatre.
"I wanted to find a way of making a comedy where characters could fully reveal themselves in a compressed place and time.  I wanted to go as deep as we possibly can, and yet laugh."
"Actors dream of projects like this," Cillian Murphy claims. "It's all about the concept and pitch nowadays, and the action, whereas this is all characters talking in a room. It happens so rarely these days."
The Party received a warm response from the international audience at its world premiere in Berlin, and was described by trade magazine Variety as "a return to form for Sally Potterâ€¦ with a caviar-black comedy".
Potter, one of four women directors in competition at the festival, says that the film was shot in black and white "as it gives a space for emotional colour" and harks back to some of her favourite films.
"It was shot in two weeks in one location, and I put my time into choosing the actors for the characters. They're all intelligent people, and it's about provoking the magic of collaboration."
"Really, I think it's the antidote to big-budget film making, which can often create numbness."
The Berlin International Film Festival runs until 19 February.
Follow us on Facebook, on Twitter @BBCNewsEnts, or on Instagram at bbcnewsents. If you have a story suggestion email entertainment.news@bbc.co.uk.


Shares in the wearable camera maker GoPro shed as much as 19% in after-hours trading in the US after the firm's latest results showed it made a loss in the December quarter.

The firm said net income losses came to $34.5m (Â£23.67m) for the period, compared with a profit of $122.3m.
It also said revenue for the current quarter would come in well below expectations.
GoPro has been facing competition from cheaper devices made by Chinese rivals.
In its earnings statement, GoPro also announced that Brian McGee would take over as chief financial officer from Jack Lazar from next month and  that it would cut production of some of its action cameras.
GoPro's new action cameras will now only include the Hero4 Black, the Hero4 Silver and the Hero4 Session.
In December, the firm re-priced its Hero4 cameras, which dented the firm's overall sales results. GoPro had said there had been weaker-than-expected demand for the device because of its initial high price.
As its earnings were released in the US, trading in the firm's shares was halted. When trading resumed after hours, its shares fell as much as 19% before recovering later to be down 8.5%.
The firm was nevertheless upbeat about its revenue numbers.
"In 2015, we recorded 16% year-over-year revenue growth and the fourth quarter represented the second highest revenue quarter in the company's history," said chief executive and founder Nicholas Woodman.
"However, growth slowed in the second half of the year and we recognize the need to develop software solutions that make it easier for our customers to offload, access and edit their GoPro content," he added.
Last month, shares of GoPro plunged as much as 28% in after-hours trading after the company said its revenue would come in below expectations.
In the year-to-date, the company's shares have lost 40.5%.


A US teenager who shot dead three students is back in police custody after escaping from prison in the state of Ohio on Thursday.

TJ Lane, 19, was recaptured early on Friday. Local police tweeted "We got him... one more to go."
Lane is serving three life sentences after pleading guilty to the murders in Chardon High School in February 2012.
Two other inmates escaped in the same incident, including 45-year-old convicted robber Clifford Opperud.
Details of how the men escaped from the Allen Oakwood Correctional Institution have not been released, but local media reported they scaled a fence during a recreation break.
At around 02:00 local time (06:00 GMT) the Lima Police Department confirmed that "Thomas Michael 'TJ' Lane III is in custody.  He has been returned to the prison."
Lane was armed with a pitchfork when he was recaptured, unconfirmed reports quoting police said.
The mother of one of Lane's victims earlier said she was fearful when she heard the news of his escape.
"I'm disgusted that it happened. I'm extremely scared and panic-stricken. I can't believe it", said Dina Parmertor, whose son Daniel, 16, was among the dead.
Clifford Opperud, who was serving a sentence for aggravated robbery, burglary and kidnapping, was caught at around 04:20 local time (08:20 GMT), police said.
A third inmate briefly escaped before being recaptured, police spokesman Andy Green said.
Lane pleaded guilty last year to three counts of aggravated murder, two counts of attempted aggravated murder and one count of felonious assault.
He used a .22-calibre pistol to fire 10 shots at a group of students in Chardon High School's cafeteria, killing Demetrius Hewlin, 16, and Russell King, 17, as well as Daniel Parmertor.
Three others were wounded in the attack, which took place when Lane was 17.
Despite evidence he suffered psychosis and hallucinations, he was found competent to be tried as an adult.
During his trial, Lane smirked and smiled as victims' relatives spoke. During his sentencing he wore a T-shirt with the word "Killer" written on it.


Some court cases could be shown live on television under proposals put forward by Scotland's judges.

Their report has recommended sentencing statements by judges and sheriffs could be shown.
The review group, chaired by Lady Dorrian, also backed the idea of live tweeting by reporters in court.
But they said broadcasting or recording of cases involving children, sexual offences and vulnerable witnesses should not be allowed.
Lord President Lord Gill, Scotland's most senior judge, ordered the review because technology had changed dramatically in the 20 years since broadcasters were first allowed to televise some proceedings.
Three or four applications are submitted each year to film in court, but permission has rarely been given.
Lord Gill said: "I am grateful to Lady Dorrian and her group for having carried out this exercise so thoroughly.
"These well-considered recommendations have the support of the judges. I accept all of the recommendations.
"They are entirely appropriate in the contemporary world. My office will now prepare guidance on the implementation of Lady Dorrian's report."
The recommendations of the report include:
A total of 17 individuals and organisations responded to a consultation process during the preparation of the report.
The report has been welcomed by the Faculty of Advocates.
Its dean, James Wolffe QC, said: "In keeping with his vision of an open and accessible justice system - a vision which I share - the Lord President has made an important announcement about televising the courts.
"While there must be safeguards to protect the interests of justice, public understanding of the work of the courts - which is fundamental to our democracy - will be enhanced by these proposals, and I welcome them."
The Law Society of Scotland has also backed the proposals.
Fiona Robb, secretary to the Law Society of Scotland's Civil Justice Committee, said: "Used responsibly, cameras in court and the use of features like live tweeting will help to demystify the law, allowing the public to gain insight into the process and improve access to justice.
"While we have previously expressed concerns about significantly increasing the jurisdiction limit of the Court of Session and the huge impact that it is likely to have on Scotland's sheriff courts, we do believe that there will be significant improvements to the running of our courts as a result of these reforms."


A student housing scheme in Belfast, which recently received planning permission, has been sold.

The scheme on Great Patrick Street has been bought by London-based Olympian Group.
It had been owned by Yorkshire-based Patton Developments, which got the scheme through planning in January. The sale price has not been disclosed.
Construction is expected to begin in July 2016.
Simon Murray-Twinn, Chief Executive Officer of Olympian Homes, said the company was "excited to be bringing forward [the development]".
He said it would contribute to the regeneration of "this much neglected area of the city centre".


It's only his second day in the job but the new Greek finance minister, Euclid Tsakalotos, has been given an immediate demonstration of the intense level of media scrutiny that the role brings.

He failed to cover up his notes after leaving key meetings with Eurogroup members as they attempt to agree a new bailout deal. Within hours commentators were trying to decode their meaning as they circulated on the internet.
The key reminder in his notes appeared to be "no triumphalism". Presumably a reference to the weekend's referendum which rejected the Eurogroup's bailout plan.
The notes also appear to have a reference to the Greek communist party, the KKE. Other commentators are speculating on what words are covered by his thumb, including what precedes "on viability grounds".
Inevitably, a few satirical versions of the note have appeared on Twitter.
However, Mr Tsakalotos is not the first politician to accidentally expose his secrets in the name of a photo-call...
In 2009, the UK's most senior counterterrorism police officer resigned after accidentally revealing secret documents as he entered Downing Street.
This led to a major anti-terror operation being brought forward due to fears that it may have been compromised.
The UK's ex-Housing Minister Caroline Flint revealed her fears about property prices in 2008. She was photographed with briefing documents that said: "We can't know how bad it will get."
But the minister wasn't too concerned about the leak, shrugging it off saying:  "These things happen."
The former governor of Alaska sparked controversy and ridicule after writing notes on her hand for a speech in 2010.
Presumably due to size constraints they were kept brief. "Energy, budget cuts, tax and lift American spirit" were written on her palm . "Budget" had been crossed out and appeared to be replaced with "tax".
US comedian Jon Stewart questioned whether the notes were actually necessary, asking: "You really need to remind yourself to lift American spirits?"
She did continue to write on her hand at certain events, but as a joke for the crowd.