Computer 'hacktivists' cause havoc targeting the websites of governments, companies and the police but who they are and what motivates them?

It is 4 o'clock in the morning and I'm waiting for a Skype call from a computer hacker on the run in Canada.
After weeks of contact through Twitter and encrypted emails with "Commander X", I should finally have the chance to speak to him in person. After an hour with no call, I give up and return to bed.
"You can never have complete certainty as to what's going on, who's involved," says Gabriella Coleman, an anthropologist at McGill University in Canada, who has spent years studying hackers operating under the banner of Anonymous.
But, she says, "not being able to fully understand who's behind the mask" is what gives Anonymous political power.
Even if you have never heard of Anonymous, you have probably seen their supporters wearing the distinctive Guy Fawkes masks made famous in the comic book series and film V for Vendetta.
The movement emerged in 2008 following an attack on the website of the Church of Scientology. Since then their targets have ranged from companies like PayPal through to politicians and governments.  But who are the people carrying out these attacks and why do they do it?
Listen to The Hackers via the Radio 4 website
File on 4: Cyber Spies
The Report: Computer hacking
"It's about the right not to be oppressed by governments or any organisation for that matter," says a young Scottish activist talking to me from a webcam in his bedroom.
"We want to fight the powers-that-be when they overstep the lines," he adds.
He goes by the nickname Dr Steelhammer, and his first operation this year was to attack Catholic Church websites over the Church's opposition to gay marriage in Scotland.
Dr Steelhammer tells me they brought down one website for half an hour - but, I wondered, what was the point?
"The internet is not some playground that corporations and governments can take basic civil liberties with and destroy them and get away with it," he says.
As far as big companies are concerned he says "we have shown that around 10,000 angry people can make them lose a lot of profit by taking down their websites."
He is referring to the notorious hacking of the Sony website in 2011 when the company's PlayStation network was taken down for weeks and millions of users accounts were accessed.
It is estimated to have cost the company over $100 million and was part of a 50-day rampage by a group of hackers known as Lulz Security - or LulzSec - which targeted organisations ranging from the FBI to Britain's Serious Organised Crime Agency (SOCA).
Over a dozen people around the world have been arrested and charged over the attacks and if convicted, they could face years in prison.
I spoke to one of them who is currently on bail - so we are not using his name. Smart and articulate, he is also a realist.
"I'm not under the illusion that we're going to change the world," he tells me, "but if we can make a big enough noise for people to notice there's a problem and scream loud enough, someone's going to take notice. That's what Anonymous is."
Although he is a skilled programmer, he says Anonymous has grown quickly because you do not need to be tech savvy to become involved.
"People who are too lazy or don't have the guts to go out and actively protest and campaign... it's so easy with Anonymous, the normal Joe can just click a button and you're away."
I find out just how easy it is in a cafe in Edinburgh where I meet a hacker, Martin - not his real name. He arrives with a netbook and, in a few minutes, shows me how to download software which has a big red button asking you to fire the laser.
If you do, it will send millions of page requests to a website or server trying to overload it, causing it to crash.
This is what worries the people who are trying to deter and catch the Anonymous hackers, like Detective Superintendent Charlie McMurdy - head of the Metropolitan Police's beefed up e-Crime unit, who has over 100 staff under her command. She classes these attacks as a "Tier One" threat.
"People tend to think it's online, it's almost like a game rather than that clicking that button is actually causing serious harm," she says.
In just a few years, Anonymous has grown from a handful of hardened hackers into a movement whose targets range from the Syrian government to paedophile websites.
Although currently at the entry level of activism, Dr Steelhammer has some advice for those pursuing Anonymous:
"What I would say to Scotland Yard, the FBI, the federal government in America is 'why are you even bothering to pursue us because there are too many of us?'"
The Hackers will be broadcast on Tuesday 27 November at 20:00 GMT on BBC Radio 4. Listen again via the Radio 4 website.


This year's Northern Ireland Open trophy has been made from trees from the famous Dark Hedges in Ballymoney blown down in a storm early last year.

A number of the trees made famous by the Games of Thrones television series were felled by Storm Gertrude.
Local wood tuner Gerard Grey was asked to harvest and craft the sacred wood into a new trophy for the event at Galgorm Castle next month.
The new trophy was on display at last week's Irish Open at Portstewart.
"I approached Gerard with a design concept to produce something unique, inspiring and beautiful," says Fergus Wallace, the founder and chief executive of PerformanceACTIVE, the Northern Ireland Open's technology partner.
"I gave myself the challenge of coming up with a trophy design that reflected the ethos and character of Northern Ireland.
"I also wanted the design to be innovative and different to reflect the new format created by the European Tour and others for this event," he added, referring to the new Shootout Sunday knockout format for the tournament which takes place form 10-13 August.
"It needed to be produced locally with features that reflect many of the positive characteristics of Northern Ireland and showcase some of the attractions that draws overseas tourists to these shores every year.
"It is a unique, one-off design, handmade with iconic images from Northern Ireland such as the Slemish Mountains, Glens of Antrim, the Giant's Causeway and NI Open host venue Galgorm Castle among other well-known tourist attractions."


Apple faces a bill of $862m (Â£565m) after losing a patent lawsuit.

The University of Wisconsin successfully claimed that Apple used its microchip technology without permission in some iPhones and iPads.
The patent, filed in 1998, is said to improve the power efficiency of microchips.
The case relates to use of the technology in the iPhone 5s, 6 and 6 Plus - but an additional lawsuit making the same claim against Apple's newest models, the 6S and 6S Plus, has also been filed.
The University of Wisconsin sued Intel over the same patent in 2008. The case was settled out of court for an undisclosed sum.
In court papers, the university claimed Apple ignored its offers to license the patent, which would mean paying a fee for its continued use.
Therefore the university said Apple was wilfully infringing the patent, something which, if the court agrees, could carry a heavier fine.
The precise amount Apple may have to pay will be decided at a later stage in the court proceedings.
Despite recent well-publicised truces between some big tech firms, fierce patent battles are still being fought in courts globally.
Last week, a judge threw out claims by graphic card specialist Nvidia that Samsung and others had infringed three of its patents.
Follow Dave Lee on Twitter @DaveLeeBBC


Kasabian have closed the 2014 Glastonbury Festival with a powerful, bombastic set that drew tens of thousands to the Pyramid Stage.

The Leicester band covered Fatboy Slim's Praise You and Gnarls Barkley's Crazy, and paid tribute to soul legend Bobby Womack, who died this weekend.
"Ten years ago, we opened the Other Stage, when I was just 23," said singer Tom Meighan.
"Thank you for this, Glastonbury. So much respect."
The stage was lit in pink as the band took the stage shortly before 22:00 BST, launching into Bumblebee, the first song from their new album 48:13.
It was their first headline slot at Glastonbury, but lead singer Meighan was an effective rabble rouser.
Dressed in a white tuxedo and bow tie, he instructed the crowd to "jump all the way back to the hot dog stands" and led an effective singalong to their closing number, LSF.
The band, who have never taken themselves too seriously, brought comedian Noel Fielding onstage dressed as Vlad the Impaler during the song of the same name.
Meighan also changed the song's refrain to "Bobby Womack - see you on the other side" in respect of the late soul star, whose hit song Across 110th Street played on the PA before Kasabian took the stage.
Compared to the po-faced Metallica and the self-consciously quirky Arcade Fire, the band appeared to be enjoying their headline slot.
"We're quite overwhelmed, we're humble," Meighan told the BBC before they took to the stage.
"But I've got a feeling about tonight. It's our turn, it's our time. We're going to take this place to pieces."
In the event, Kasabian drew a slightly bigger audience (an estimated 100,000) than either of the other headliners - but not as big as Dolly Parton earlier on Sunday.
The final day of the festival opened with a performance from the English National Ballet, who paid tribute to those who died in World War One.
Their performance, Dust, was choreographed by Akram Khan, who helped put together the opening of the London 2012 Olympics with Danny Boyle.
Sombre but powerful, the performance moved some in the early morning audience to tears.
Other acts on the final day included Ed Sheeran, who played the Pyramid Stage unaccompanied, using his acoustic guitar and a series of effects pedals.
Despite breaking several strings along the way, he was warmly welcomed by the crowd in the mid-afternoon heat.
On The Other Stage, Ellie Goulding delivered an energetic, full-throttle run-through of her biggest dance hits as the sun set, while Disclosure brought several special guest vocalists - including Eliza Doolitle, Sam Smith and Aluna Francis to their headline set at the West Holts stage.
Against the bombast of Kasabian, Glastonbury organisers had programmed some more mellow bands to aid the come-down at the end of the festival.
Massive Attack's hushed version of Teardrops was a highlight on The Other Stage, while London Grammar's lush, melancholy album If You Wait drew huge crowds to the John Peel Stage.
The turnout will have pleased the Brit nominees, who admitted to suffering from a bad case of the jitters before they went on stage.
"I'm terrified," singer Hannah Reid told the BBC, two hours before showtime.
"You struggle to feel worthy for Glastonbury. I'm like 'oh no, I'm really a fraud. I can't sing at all and everyone at Glastonbury's going to know'."
But Dolly Parton was the star turn of the day, if not the festival.
She charmed the crowd with her ornery banter and diamante-studded hairpiece, and led lusty singalongs to hits such as 9 to 5, Jolene and I Will Always Love You.
"Thanks for singing along with me, I heard you out there," she said, sounding genuinely delighted.
For the first, and probably last, time Parton also performed a song about Glastonbury's mud that she had written in the early hours of Sunday morning, which included the lyrics: "Mud, mud, mud, mud/Up to our bums in all this crud."
The mud will be traded for traffic jams during Monday as the 175,000 revellers leave Worthy Farm and head back home.
But festival organiser Michael Eavis has confirmed the event will be back next year, and that he's already booked all three headliners.
Prince - widely rumoured to top the bill this year - is still refusing to come to Somerset, but at least one of the bands will be coming from abroad.
"The agent of the band was here last night," Eavis told the BBC.
"He was watching Metallica on the platform with me, and he said 'my band want to play a show at Glastonbury next year'. So that deal was done on the platform last night."


An historic blizzard has struck large parts of the eastern United States, dumping 102cm (40in) of snow in only a few hours in places.

As day broke on Saturday, the extent of the overnight snowfall became clear - and it got only worse as the weekend went on.


Advice to boil tap water before drinking it has been lifted in 86,000 more homes in Lancashire.

Residents have had to boil drinking water for three weeks after a parasite discovery at a treatment works.
Some 300,000 homes were initially affected, half of which can now use water as normal.
Parts of Chorley, Preston and South Ribble are the latest to be given the all clear from water firm United Utilities.
It has assessed hundreds of test results after discussions with Public Health England.
Action was taken after the microbial parasite cryptosporidium was found near Preston on 6 August.
Water has been treated with ultra violet (UV) light to kill the parasite, which can cause diarrhoea and cramps.
A petition calling for a parliamentary inquiry into how the bug entered the water supply has been signed by about 12,000 people.
The water firm said it hoped to lift restrictions for people in the Fylde coast area on Wednesday.
Customers can check which areas have had restrictions lifted by visiting the United Utilities website or calling 0800 912 7241.


Egypt has added ex-football star Mohamed Aboutrika to a terror list for his alleged links with the banned Muslim Brotherhood, his lawyer says.

Mr Aboutrika is accused of financially supporting the Brotherhood, which Egypt considers a terrorist organisation.
In 2012, he endorsed the successful presidential bid by Mohamed Morsi, a Brotherhood member.
The move by the 2008 BBC African Footballer of the Year alienated some of his fans.
Any person named on the country's terror list is subject to a travel ban and faces having their passport and assets frozen.
Mr Aboutrika's lawyer, Mohamed Osman, said the move was "contrary to the law", adding that his client had "not been convicted or formally notified of any of the charges against him".
"We will appeal this decision," Mr Osman said. Mr Aboutrika has strenuously denied the allegations.
A former star of Cairo's al-Ahly club and the national team, Mr Aboutrika was dubbed The Prince of Hearts, The Magician and The Saint during his playing days.
But his decision to publicly support Mr Morsi, who lasted just one year in power, split opinion.
In 2015, he had a string of assets, including shares in a number of companies, seized by the Egyptian authorities.
The army's crackdown on Brotherhood members, left hundreds of people dead and thousands in jail.
Mr Morsi was ousted following days of mass anti-government protests in 2013.
Mr Aboutrika, one of the most successful African footballers of his generation, retired from football in the same year.


More needs to be done to increase the number of eels around the world, according to conservationists.

Their numbers have dropped dramatically in the last 30 years. but experts have just completed the first year of a big project to protect the places where they live.
Jenny spoke to Matt Gollock, from the Zoological Society of London, about why the creatures are at risk.
European eels are the great travellers that migrate thousands of miles.
It's thought the creatures start their journey as eggs in the Sargasso Sea, in the Western Atlantic near the Bahamas.
The eggs then hatch into transparent larvae called leptocephalus.
They then make the journey to Europe floating on the oceans currents.
Eel larvae from the Sargasso Sea can take up to three years to reach Europe.
By the time they reach our shores in the UK, they have developed into tiny glass eels that swim against the current into Europe's rivers.
In shallow waters they become elvers which move together upwards into estuaries and river systems.
While living in our rivers the eels are called yellow eels.
They can grow up to 1m long, with female eels being much longer than males.
Here they will spend many years before becoming silver eels and returning to the open sea for the long journey back to the Sargasso
Once back in the Sargasso Sea it's thought they spawn and lay eggs, but this has never been seen.
Experts believe the eel dies after it's reproduced.


Patients at a GP surgery in Kent are at "unacceptable levels of risk", the Care Quality Commission (CQC) has said.

During an inspection, officials found Dr Bijan Saha's surgery in Sittingbourne failed to meet 11 standards of safety and patient care.
They identified "serious failings" at the Lakeside Medical Centre, including problems with privacy for patients, cleanliness and medication errors.
Dr Saha told the BBC he had no comment to make.
He is assisted by a GP, a practice manager and three administrative staff.
The regulator said it would be taking action against Dr Saha, who runs the practice in Todd Crescent, Church Milton, but no further details could be given for legal reasons.
Michele Golden, CQC's head of GP inspection in the South, said: "The issues that we have identified at Dr Saha's practice are very serious and we'd urge anyone who uses it to read our full report.
"We've shared our concerns with the rest of the local health economy and have asked that they also consider what action they may need to take to ensure that people using services at this practice are protected from harm.
"People using this practice are currently at unacceptable levels of risk and keeping them safe is a job for all of us."
Dr Saha was still practising but "under very close supervision from local health bodies including NHS England, a CQC spokesman added.
Outside the surgery on Wednesday, some patients criticised the care they had received.
Gwen Willmott, who left the practice, said: "I wasn't happy with the situation. My husband died and I thought he could have had better treatment from them."
Swale councillor Mike Whiting said it had concerned residents in the area.
But he emphasised the practice was still in operation: "I've been down here today and I've spoken to the receptionist in there and it is business as usual in the surgery."
During the unannounced inspection in March, inspectors found the practice failed to meet national standards of care in 11 areas.
Patients told inspectors that practice staff would talk about other cases in their presence - breaching patient confidentiality.
A CQC spokesman added: "Repeat prescriptions were issued without reviews having taken place and were often printed by administrative staff on the verbal instructions of Dr Saha.
"This procedure had led to a prescribing error which could have had very serious consequences for the patient concerned."
Katherine Murphy, chief executive of the Patients Association, said: "These findings are shocking and cause a great concern to us.
"GPs are the first port of call for patients and to be faced with such poor quality of service is completely unacceptable."


Partick Thistle manager Alan Archibald points to the procession of coaches coming to Scotland to attain their Uefa licence as proof that the standard of coaching in Scotland is high.

Archibald was responding to comments by his former player Ziggy Gordon that he has learned more in a few months in Poland than in his years in Scotland.
"I don't think he's trying to downgrade the standard here," said the Jags boss.
"I just think he has learned a little bit more abroad."
Jose Mourinho, Costinha, Andre Villas-Boas, Brendan Rodgers, Pedro Caixinha and Alan Shearer are among those who have come to Scotland to sit their Uefa Pro licence over the years.
Archibald, who is on the four-man shortlist for the PFA Scotland manager of the year award, said he had never seen Polish coaches at work so did not know how accurate the Jagiellonia Bialystok defender's comments were.
"I've never been there, so I don't know where he's coming from," said the Jags boss.
"But I think when any player goes abroad, you'll pick something up. Your eyes are opened wide, and you'll learn something a little bit different."
Further, Archibald said the standard of coaching in Scotland was "very good".
He continued: "I think a lot of top coaches come here to do their coaching badges so we must be doing something right.
"As (Celtic manager) Brendan Rodgers says, you get a challenge every week. This has probably been the best season in terms of the challenge, tactically.
"All the managers are now playing different shapes and changing it during games as well, so I think all coaches are tactically very aware and they all do their homework now as well.
"I don't think any team just turns up on a Saturday and says 'right, on you go, go and play'. There's a lot of work going in during the week from every team in the league."
Archibald admitted to being taken aback to be nominated by his peers as Scotland's top manager this season, along with Rodgers, Aberdeen's Derek McInnes and Morton's Jim Duffy.
"I think (I'm surprised) just because we've not won anything," said the manager, whose team reached the Premiership's top six for the first time.
"Brendan's won trophies, Derek's been to semi-finals and finals and so has Jim.
"We are sixth and sometimes from the outside people don't know how hard you work, or what it takes to get there.
"Making the top six is huge to a club like ours, and sometimes it's as good as winning a trophy."


A motorcycle stuntman was airlifted to hospital after an accident during a "wall of death" performance at the Royal Cornwall Show.

The rider, troupe owner Ken Fox, was taken to Derriford Hospital, Plymouth after falling from the top of the cylindrical track.
An eyewitness told BBC News: "There was an air of panic with people screaming and running out of the tent."
Mr Fox, from Cambridge, was treated for bumps, bruises and scratches.
Emergency services remain on the scene at the showground in Wadebridge speaking to witnesses.
On Facebook, Ken Fox Wall of Death said in response to concerns for the rider: "Ken Fox is safe and well just a bit bashed about."
Devon and Cornwall Police say nobody else was injured in the accident.
The wall of death is a motorcycle show in which stuntmen ride at speed around a vertical track performing tricks and stunts on 1920 Indian Scout bikes.
The Ken Fox Wall of Death troupe has been featured in music video and on television, including the BBC One idents showing stunt riders going round in a circle.
The eyewitness said the rider fell from the top of the wall on to his head but he could not see why he fell.
People outside said they heard a huge bang and that they felt the earth shake.


Pakistan may boycott next year's World Twenty20 if India fail to play a proposed series with them this year.

The arch-rivals have yet to agree the first of six proposed series between 2015 and 2023.
Talks were disrupted after far-right Hindu nationalists attacked Board of Control for Cricket in India offices, protesting against games with Pakistan.
The Pakistan Cricket Board warned their government "will say don't go" if India do not agree to a series this winter.
The 2016 World Twenty20 is due to be held in India in March and April.
India and Pakistan have not played a bilateral Test series since 2007 after New Delhi stalled the ties in the aftermath of terrorist attacks on Mumbai in 2008, blamed on militants based across the border.
India were due to play two Tests, five one-day internationals and two Twenty20 internationals this year in the United Arab Emirates, where Pakistan play their home Tests because of security concerns in their own country.
In addition to talks being scrapped, Pakistani umpire Aleem Dar was withdrawn from India's home series with South Africa by the International Cricket Council (ICC).


Two Palestinians and a Jordanian have been shot dead in separate attacks on Israelis in East Jerusalem and the West Bank, Israeli officials say.

Two of the incidents occurred near the flashpoint West Bank city of Hebron, while the third happened outside a gate to Jerusalem's Old City.
It is the first such spate of attacks after months of near-daily stabbings and car-rammings recently subsided.
A Palestinian was also shot dead when Israeli troops raided his home.
Mohammed Saraheen, 30, was killed while trying to evade arrest during the operation in the West Bank village of Beit Ula on Friday morning, the Israeli military said.
Two of the later attacks on Israelis happened nearby.
In one, a Palestinian was shot dead after ramming his vehicle into civilians at a bus stop near the Israeli settlement of Kiryat Arba, the military said. Three people were wounded.
Another Palestinian who was involved in the attack was shot and wounded, officials said.
Hours later, a Palestinian who stabbed and wounded a soldier at a junction near Hebron was shot dead, officials said.
In East Jerusalem, a Jordanian man was killed by security forces after trying to stab police outside Damascus Gate, according to Israeli authorities.
The site has been the scene of multiple attacks on Israelis, and killings of assailants, in previous months.
Thirty-five Israelis been killed in a wave of knife, gun and car-ramming attacks by Palestinians or Israeli Arabs since last October.
More than 200 Palestinians - mostly attackers, Israel says - have also been killed in that period.
Israel says Palestinian incitement has fuelled the attacks. The Palestinian leadership has blamed frustration rooted in decades of Israeli occupation.


Two of Oscar Pistorius's watches went missing from the crime scene, a former South African police officer told the athlete's murder trial.

Col Schoombie van Rensburg said he had been "furious" at the disappearances and had ordered officers to be body-searched for the "expensive" watches.
The court was also shown a photo of Mr Pistorius in blood-covered shorts.
He denies murdering his girlfriend Reeva Steenkamp last year, saying he mistook her for an intruder.
The prosecution says he intentionally shot Ms Steenkamp after an argument at his house on Valentine's Day 2013.
Friday's hearing has now been adjourned and the trial continues on Monday.
Col Van Rensburg, who was initially in charge of the crime scene, said that when he first saw the watches he was worried about them and ordered them to be photographed because they "looked expensive".
By Pumza FihlaniBBC News, Pretoria
The competence of South Africa's police is often under the spotlight, especially when it comes to the handling of crime scenes, and there have been a few embarrassing moments for them at the trial.
The court heard that two watches were allegedly stolen from the house and a ballistics expert handled the gun without gloves.
We have previously heard shoe marks were found on the toilet door - a vital piece of evidence.
While this does not discredit the state's entire case, it does not show the local police in a good light.
Some have likened the Pistorius case to the OJ Simpson trial. Much like the OJ case, which was pinned on circumstantial evidence, the prosecution is relying on the police to help prove their case.
With the world watching, local law enforcement will doubtless be feeling the pressure. They will not want to be blamed for jeopardising such a high-profile case.
After returning to the main bedroom where a team of forensic experts was gathering evidence, he realised one watch, said to be worth as much as $10,000 (Â£6,000) was missing. He said he was told Mr Pistorius' sister Aimee had come into the room and removed it.
After leaving the room again, another watch went missing, so he gave instructions for the police officers and their cars to be searched.
Col Van Rensburg said that after that, everyone entering and leaving the scene was thoroughly searched and entered into a log, presented in court.
He described his stunned reaction to the watches' disappearance: "I said: 'I can't believe it. We were just there. How can this watch be gone?'"
He said he told Mr Pistorius he should file a complaint, while he opened a case of theft.
The former officer, who retired last year, also told the court he was angry when he saw a ballistics expert handling Mr Pistorius' 9mm pistol without any gloves, and told him to put some on.
The admissions call into question the police's handling of the crime scene, in a case that is likely to hinge on sensitive forensic evidence, correspondents say.
Col Van Rensburg also said he saw Mr Pistorius with blood on his arm, while the court was shown a photograph of the South African Paralympic athlete with blood on his shorts and parts of his body.
Mr Pistorius says he carried Ms Steenkamp downstairs to try to save her.
On Thursday, Col Van Rensburg told the court in the capital, Pretoria, he had followed a "trail of blood" up the stairs after arriving at Oscar Pistorius' home.
Before Col Van Rensburg began his testimony on Thursday, photographs of Ms Steenkamp's bloodied head and face were shown in court, prompting Mr Pistorius to vomit.
The athlete was sick several times on Monday while evidence from the post-mortem examination was presented to court and has also cried on several occasions.
The court was later told that photos of her body would be removed from the police file and not displayed in court.
The BBC's Pumza Fihlani, who was in court, says images of the deceased's body are often shown during trials and the decision could fuel a perception that South African courts give special treatment to the rich and famous.
1
2
5
4
6
3
Mr Pistorius said in his statement at the start of the trial that he woke in the early hours and  walked on his stumps to the balcony, pulled in two fans, closed the sliding door and drew curtains. He said that shortly before he had spoken to Reeva, who was in bed beside him.
He said he rejected prosecution claims that a witness heard arguing coming from the house before the shooting.
Mr Pistorius said he heard the bathroom window sliding open and believed that an intruder, or intruders, had entered the bathroom through a window which was not fitted with burglar bars.
"Unbeknown to me, Reeva must have gone to the toilet in the bathroom at the time I brought in the fans," he said.
Mr Pistorius said he approached the bathroom armed with his firearm, to defend himself and his girlfriend, believing Ms Steenkamp was still in bed.
Both sides agree four bullets were fired. Ms Steenkamp was hit three times.
Mr Pistorius said he fired his weapon after hearing a noise in the toilet which he thought was the intruder coming out of the toilet to attack him and Ms Steenkamp.
He said he was in a fearful state, knowing he was on his stumps and unable to run away or properly defend himself.
Mr Pistorius said he rejected claims that he was on his prostheses when he shot at the door.
A witness told the trial she woke to hear a woman screaming and a man shouting for help. She said that after the screams she heard four shots.
Mr Pistorius said he went back to the bedroom after shooting at the toilet door, still shouting for Reeva. Lifting himself up onto the bed, he felt over to the right hand side of it and noticed Ms Steenkamp was not there.
Mr Pistorius said this was when he realised she could have been in the toilet.
Mr Pistorius said he went back to the bathroom but the toilet was locked, so he returned to the bedroom, pulled on his prosthetic legs, turned on the lights before bashing in the toilet door with a cricket bat.
Forensics expert Johannes Vermeulen told the court that the height of the marks on the door caused by the cricket bat suggest Mr Pistorius was on his stumps at the time.
Mr Pistorius's defence team say he then called security at the gated housing complex and a private paramedic service before carrying Ms Steenkamp downstairs.
A security guard claimed it was the other way round, and he had called Mr Pistorius first after reports of gunfire. However, phone records shown to the court revealed Mr Pistorius called the estate manager at 3:19am, a minute later he called the ambulance service and at 3:21am he called estate security.
A minute later he received an incoming call - estate security calling him back.
According to police phone expert Francois Moller, Mr Pistorius called his friend Justin Divaris a short time later and just after 4:00am he called his brother Carl.
The trial, now in its 10th day, is expected to call on more than 100 witnesses. It had been set to last for three weeks but looks likely to be extended.
The state is seeking to convince the court that Mr Pistorius and Ms Steenkamp - a 29-year-old model, reality TV star and law graduate - had an argument before he fired the shots that killed her.
There are no juries at trials in South Africa, and his fate will ultimately be decided by the judge, assisted by two assessors.
If found guilty, the 27-year-old - a national sporting hero and double amputee dubbed the "blade runner" because of the prosthetic limbs he wears to race - could face life imprisonment.


Check out BBC Wales Sport highlights of Sunday's 16-16 Six Nations draw between Ireland and Wales in a delicious bitesize 30 seconds (ish) chunk.

Media playback is not supported on this device


The aerospace company that pioneered in-flight refuelling has asked shareholders for a £500m injection to repair its finances - the second such cash call in just eight months.

Cobham unveiled the rights issue plan alongside a disastrous set of results.
The firm is still trading profitably and made a £225m operating profit.
But it was thumped heavily into the red after it wrote down the underlying value of its business. It declared a statutory pre-tax loss of nearly £850m.
Cobham - whose founder, Sir Alan Cobham, was one of the pioneers of British aviation - has annual sales of £2bn.
The rights issue will be a blow to shareholders, who were stunned last June when the company asked for another £500m. It then said the money would put it on a "sound financial footing".
Analysts were puzzled when the company did not cancel its dividend payment to shareholders - worth £125m a year - at the time.
With the latest rights issue - which has been underwritten by a group of investment banks, meaning the company is sure to get the money even if investors decline to put more money in - the dividend has been scrapped.
Cobham chairman Michael Waring said while there had been significant management change in recent months, there would be more to come, promising "a rolling programme of board changes over the next two years".
David Lockwood, chief executive since last summer, said he was confident Cobham could be "reinvigorated over time".


A disabled man claims a High Court judge acted unlawfully when giving medics permission to remove him from his home to hospital and authorising the use of force.

Aamir Mazhar, who has muscular dystrophy, says the order by Mr Justice Mostyn infringed his human rights.
He has taken legal action against Liz Truss, the Lord Chancellor and Justice Secretary, who disputes the claim.
Mr Mazhar's lawyers claim there was "no basis" for making the order.
See more stories from across Birmingham and the Black Country here
Mr Mazhar, 27, from Birmingham, says his rights to liberty and respect for private and family life were breached when he was "forcibly removed" from his home 13 months ago.
A more senior judge is analysing the case at a trial in the Family Division of the High Court.
Court of Appeal judge Sir Ernest Ryder has been asked to declare that Mr Justice Mostyn's order was "unlawful".
Birmingham Community Healthcare NHS Trust had asked Mr Justice Mostyn to make the order at an out-of-hours telephone hearing in April 2016, the court heard.
Sir Ernest heard Mr Mazhar had made a separate damages claim against the trust which had been settled.
At a hearing in June 2016, lawyers representing the trust said staff had made an emergency application as they were facing a critical situation.
They said a "care package" provided to Mr Mazhar at his home had "broken down" and staff thought that Mr Mazhar was at risk of serious injury or death.
However, lawyers representing Mr Mazhar told Sir Ernest on Wednesday there had been "no basis" for the making of the order.
The trial continues.


At least 21 people have been killed in a bomb blast in northern Nigeria as they were watching a World Cup match, a hospital source has told the BBC.

Witnesses in Damaturu, in Yobe state, say a suicide bomber in a tricycle taxi detonated explosives as people watched Brazil's match against Mexico on TV.
At least 27 people are said to have been seriously injured.
Public screenings of the World Cup in some parts of Nigeria have been banned because of threats by Boko Haram.
Three states, including Yobe, are under a government-imposed state of emergency following years of attacks.
No group has said it was behind the latest blast.
Kaduna's football fans have mixed views. While some say they will now stay away from viewing centres because they are scared, others say they will still go, but with caution.
Many say they enjoy going to the centres too much to stop. As well as watching the games with their friends, they enjoy arguing, analyzing and betting on the matches. Others say that after the bombing, they will stay away as they do not want to lose their lives for the sake of watching a football game.
Lynda, a student and a football fan says: "During the Champions League final between Atletico and Real Madrid, I was in a viewing centre when I heard that another one was bombed in Jos. I was scared but I had to finishing watching the match before going home.
"In as much as they are bombing, we just hope that it does not get us, but it is not enough to make people stop going to viewing centres."
There have also been warnings of potential attacks at venues showing the World Cup in East Africa - Somali Islamist group al-Shabab killed 76 people watching the 2010 World Cup final at two restaurants in the Ugandan capital, Kampala.
Both Boko Haram and al-Shabab say watching football is unIslamic - a view rejected by mainstream Muslims.
The Yobe local police chief has told the BBC that the attack happened outside a shop with a television, where people had gathered to watch the game.
He said it was not a viewing centre where Nigerians often watch football matches, as these have been banned in the state.
Other sources say it was a viewing centre which was attacked.
While the police say 13 people died, the hospital worker told the BBC he had personally counted 21 bodies.
Correspondents say Nigeria's authorities often downplay the number of casualties.
In another development, the authorities say a senior Boko Haram militant was among almost 500 northerners arrested as they travelled to Nigeria's oil hub of Port Harcourt earlier this week.
The authorities did not name the suspect. Relatives of those arrested say they had no links to Boko Haram and had gone to southern Nigeria for economic reasons.
The Damaturu hospital worker said truckloads of injured people were being treated in overcrowded wards after the explosion on Tuesday evening.
"The military and police trucks that brought them in have made four return trips so far ferrying them in," the worker said.
"Every single truck was full of the injured. And all of them are young men or children."
The worker said that the injuries suffered by people caught up in the blast were "horrific".
Damaturu resident Mohammed Kurkure Yobe told the BBC that the venue where the attack took place was very popular and often crowded with people watching big events.
Open-air viewing centres - where people pay to watch live football - are popular throughout Nigeria.
On 1 June at least 14 people were killed in a bomb attack on a bar in Adamawa that was screening a televised football match. No group claimed responsibility for the blast.
In March, many people were also killed in explosions while watching football in a video hall in Borno's Maiduguri town. On both occasions, Boko Haram was blamed for the blasts.
Boko Haram - which means "Western education is forbidden" in the Hausa language - wants to overthrow the government and create an Islamic state.
The group captured international attention in April after it abducted more than 200 girls in Chibok in Borno state.
The states of Borno, Yobe and Adamawa have been under a state of emergency since May 2013. Thousands have died in the north-east since Boko Haram launched an insurgency in 2009.
Nigeria's military has promised increased security but there are still daily reports of attacks on villages in parts of the north-east.


England's "old-fashioned" policy of only selecting domestic-based players should be scrapped, says former national team coach Sir Clive Woodward.

The 2003 World Cup winning coach congratulated Australia for announcing a partial reversal of their policy to omit Australians playing overseas.
"Stuart Lancaster must be free to pick his best players, no matter where they ply their trade," he said.
"It's wrong to say England are best served by players at English clubs."
Woodward pointed to Toulon's Steffon Armitage and Clermont Auvergne's Nick Abendanon as examples of foreign-based players who deserve to be considered for the English national team.
He added, in the Daily Mail: "Jonny Wilkinson moved to France and became even better than when he played for England, so that completes the argument for me. Would I have picked Jonny if he was playing in France? Of course I would."
Woodward also said if players such as Matt Giteau and Drew Mitchell of Toulon were to excel for Australia against World Cup hosts England later this year then everyone would "know exactly what the headlines will be".
He added: "When it comes to a home World Cup, you don't want to be left talking about 'what ifs'."
Lancaster's England side play Australia, Wales, Fiji and Uruguay in the World Cup group stages, with their opening game against Fiji to be played at Twickenham on 18 September.


England striker Jermain Defoe says the squad's visit to a Royal Marines boot camp could help the players cope with the emotion of penalty shootouts.

Defoe said having his team-mates watching him complete the 'sheep dip' was a "pressure moment".
"It's the sort of pressure when you're in a penalty shootout and the lads are waiting for you to step up," he said.
"Going forward it helps you, brings you closer together. You know you've got your team-mates who will help you."
England manager Gareth Southgate arranged the trip to a Commando Training Centre in Devon as part of their preparation for Saturday's World Cup qualifier against Scotland, and a friendly with France three days later.
Twenty England players were taken out of their comfort zones in the 48-hour boot camp designed for Marine recruits.
"It was the perfect thing to do if you want team-bonding," added Defoe, who is on the verge of joining Bournemouth from Sunderland after completing a medical.
"No phones, doing everything together, the whole experience was so unique, camping out with rations."
Goalkeeper Jack Butland said the camp was "one of the most rewarding experiences" he has ever had.
"I think as a squad and players we all benefited from that," he said. "There was a lot to learn, stuff that we're keen to take forward in what we're trying to achieve.
"We always want to achieve as well as we can do but if you keep preparing the same, you'll get the same results.
"I think that's something that Gareth lives by and it's important that we stretch ourselves."
Meanwhile, Butland says his "healthy" rivalry with fellow England goalkeeper Joe Hart is a positive for the national side.
The Stoke keeper, 24, has returned to the squad after a year of injury problems which started on England duty in Germany last March.
Butland is one of four goalkeepers in the squad but first trained with Hart, who is likely to start against Scotland on Saturday, when the pair were at Birmingham City.
"I've known Joe a long time," he said. "We've always had a healthy relationship.
"I think that bodes really well when we come into squads. I'm keen to do as well as I can and in turn that pushes him and likewise pushes me back.
"It's really healthy and positive and it gets the best out of each other."


Egypt's state prosecutor has issued an arrest warrant for the leader of the Muslim Brotherhood, Mohamed Badie, and at least nine other senior figures.

Mr Badie is accused of inciting the violence in Cairo on Monday in which more than 50 people were killed.
Many Brotherhood members are already in detention and warrants are said to have been been issued for hundreds more.
Meanwhile, a foreign ministry spokesman has said ousted President Mohammed Morsi is being held in a "safe place".
Badr Abdul Atti told reporters he did not know where the 61 year old was, but that he was being treated in a "very dignified manner".
"For his own safety and for the safety of the country, it is better to keep him in a safe place. Otherwise, the consequences will be dire," he added.
Mr Abdul Atti is reported to have denied that Mr Morsi was being detained at the Presidential Guard barracks in Cairo, as many believe.
The Brotherhood, to which he belongs, says his ousting by the military a week ago amounted to a coup.
Its supporters have since been staging protests outside the capital's Rabaa al-Adawiya mosque, not far from the barracks, demanding his release and reinstatement.
By Wyre DaviesBBC News, Cairo
Muslim Brotherhood spokesmen were almost baffled by the prosecutor's move to issue arrest warrants for Mohammed Badie.
Mr Badie is the movement's general or supreme guide, to whom every new member is required to pledge an oath of allegiance. So, his detention would enrage the thousands of Brotherhood supporters camped outside Cairo's Rabaa al-Adawiya mosque, where they are vowing to remain until President Mohammed Morsi is released and reinstated.
Mr Badie and a handful of other Brotherhood leaders escaped arrest when the army deposed Mr Morsi a week ago. He has since addressed the crowd at the mosque and vowed not to give an inch until the democratically elected government is restored.
The real danger is that the move to arrest Mr Badie completely undermines efforts by the interim president to form a government of national unity, ahead of proposed elections next year. Less than 24 hours ago, Adly Mansour's office was reporting that it had offered positions to the Brotherhood.
But any attempt to arrest those senior Brotherhood figures not yet in detention would almost certainly inflame what is already a volatile situation in Egypt.
The movement's political wing, the Freedom and Justice Party (FJP), has said it will not accept an offer to join the cabinet being set up by interim Prime Minister Hazem al-Beblawi, a 76-year-old economist and former finance minister who was appointed on Tuesday.
The arrest warrants could scupper any attempts to persuade the Brotherhood to participate in the transitional political process.
Spokesman Gehad el-Haddad said the charges against Mr Badie, known as the General Guide, and other senior leaders, were "nothing more than an attempt by the police state to dismantle the Rabaa protest".
Prosecutors also said they had ordered 200 people - believed to be Brotherhood members - to be held in custody for at least 15 days pending further investigation into accusations of murder, incitement to violence, carrying unlicensed weapons and disrupting public order. Another 450 have been released on bail.
There were conflicting reports about what happened on Monday, with the interim authorities being accused of a cover-up.
The Brotherhood maintains that soldiers carried out a massacre of peaceful demonstrators, who had been taking part in dawn prayers outside the Presidential Guard barracks.
But the police and the military say they acted in self-defence, and had opened fire only after being attacked by armed assailants.
More than 50 Brotherhood supporters were killed, as well as a soldier and two policemen.
On Wednesday, 15 leading Egyptian human rights groups expressed their "strong condemnation of the excessive use of force" against Brotherhood supporters, and called for an independent investigation into Monday's violence.
Egypt authorities accused of cover-up
Egypt clashes: Divided views
Is Egypt heading for holy war?
The previous Friday, Mr Badie had appeared at a rally outside the mosque, telling the crowd: "We shall stay in the squares until we bring President Morsi back to power."
He said their protests would remain peaceful and called on the army not to "direct your arms against us".
The BBC's Jim Muir, in Cairo, says the protest now covers several square kilometres of the capital, and to clear it out forcibly would almost certainly involve further bloodshed.
There is a feeling among the protesters that they have returned to the situation they were in under former President Hosni Mubarak, when the movement was banned and its members hunted down, our correspondent adds.
The timetable for new elections, announced in a constitutional declaration by interim President Adly Mansour on Monday evening, laid out plans to set up a panel to amend the suspended constitution within 15 days.
The changes would then be put to a referendum - to be organised within four months - which would pave the way for parliamentary elections, possibly in early 2014.
Key players in the Egyptian crisis
Profile: Hazem el-Beblawi
Q&A: Egypt in turmoil
Once the new parliament convenes, elections would be called to appoint a new president.
A spokesman for Mr Mansour said posts in the cabinet would be offered to the FJP, but senior party official Mohamed Kamal told the BBC: "We will never take part in any cabinet as long as Morsi is not back as a president."
The FJP's deputy chairman, Essam al-Erian, earlier said the constitutional declaration had been issued "by a man appointed by putschists". The text does make clear that Mr Mansour and his government draw their authority only from the commander of the armed forces, who deposed President Morsi.
The main liberal coalition, the National Salvation Front (NSF), expressed reservations about the decree, saying it was not consulted and that it "lacks significant clauses while others need change or removal".
The grassroots Tamarod protest movement, which organised the demonstrations that led to Mr Morsi's overthrow, said the decree gave too much power to Mr Mansour.
Meanwhile, Saudi Arabia, the United Arab Emirates and Kuwait - who are opponents of the Muslim Brotherhood - have promised Egypt's interim government $12bn (Â£8bn) in grants, loans, and gas and oil.
Lyse Doucet: The struggle to save Egypt's revolution
Frank Gardner: Is Egypt heading for holy war?
Key players in the Egyptian crisis
Egypt clashes: Divided views


Retailer Argos is to open ten pilot digital stores in Sainsbury's that will aim to offer a broad range of general merchandise.

People will be able to order Argos products online, and then collect them in the supermarket locations the same or the following day, Argos said.
Sainsbury's has seen strong demand for non-food products over the past three years.
And in November it found that 6% of shop-floor space was being under-used.
The supermarket giant aims to fill half of that space with clothing lines, and devote half of the space to general merchandise.
"These 10 Argos stores will complement our supermarket offer, giving customers the opportunity to shop for an extended range of non-food items," said Mike Coupe, chief executive of Sainsbury's.
Argos customers can already order products online to be delivered by post, or can opt for so-called 'click-and-collect' - which Argos calls 'check and reserve'.
Check and reserve is important to Argos - it accounts for a third of Argos' total sales.
The digital pilot, which will be in 10 Sainsbury's supermarkets with a floor space of between 30,000 to 100,000 square feet, will be in shops dotted around the UK.
Possible locations of the concessions have been identified, and should be announced within the next few weeks, a Sainsbury's spokeswoman said.
The concessions are likely to be located in areas which are further away from existing Argos shops.
Around 1,000 products will be held in stock in the supermarket, and about 20,000 products will be available to collect the same or following day. Products that are not held in the supermarket will be delivered from one of 140 larger Argos stores.
Argos has ten concessions in Homebase DIY stores - both companies are part of the Home Retail Group.
Sainsbury's already has concessions from around 30 different firms in its shops.
Shoe repair firm Timpson, camera company Jessops, and Virgin Holidays and Thomas Cook travel agents all operate Sainsbury's concessions.
In November, Sainsbury's reined back plans for new shops, saying that like-for-like sales had fallen in the half-year.


Manchester City captain Vincent Kompany has not been given any guarantee over his first-team place when he finally recovers from his groin injury.

Kompany, 30, suffered the injury against Real Madrid on 4 May.
City manager Pep Guardiola says the defender is close to full fitness but not in time for Saturday's Premier League game against Bournemouth.
"The players must compete with each other," said Guardiola. "We'll see on the pitch what is best for each game."
Kompany has been an automatic choice since his arrival from Hamburg for around £10m in 2008.
He replaced Carlos Tevez as City captain following the 2011 FA Cup final victory over Stoke and in his 298 appearances for the club has led them to two Premier League titles and two League Cup final victories.
In recent seasons though, he has suffered a number of muscular injuries.
Last year he was missing for over a month on four occasions prior to the injury that ended his season and meant he was not able to play for Belgium at Euro 2016.
His highest number of Premier League appearances in the past four full seasons was 28 in 2013-14 and he only played half that number of games last term.
So, with City chasing an eighth successive win - which would be a club record from the start of the season - against Bournemouth this weekend, and £47.5m new signing John Stones excelling alongside Aleksander Kolarov and Nicolas Otamendi in defence, Kompany cannot take his return for granted.
"I know Vincent's quality," said Guardiola. "I need him to put pressure on John Stones, Nico Otamendi and Kolarov.
"They have to know if they don't play good that there's another one beside me and the next time he is going to play."
Subscribe to the BBC Sport newsletter to get our pick of news, features and video sent to your inbox.


The number of arrests for drink-driving over Christmas in Northern Ireland fell, despite police more than doubling the amount of tests.

The PSNI have revealed that 383 drivers were arrested between 24 November and 3 January.
This represents a 4% decrease compared to the same period in 2015/16.
Nearly 11,000 drivers were breathalysed during that period - a 125% rise in the number of people tested.
Almost 300 other drivers received a warning after testing positive for alcohol, but within the legal limit.
Ass Ch Cons Alan Todd said the offenders ranged from teenagers to people in their 80s.
"One person was detected at over four times the drink-drive limit, with a reading of 149 micrograms of alcohol in 100 millimetres of breath.
"We've had people literally falling out of their cars and people detected throughout the day and night across the country.
"Nearly 400 people across Northern Ireland are now facing the stark reality of a court appearance where they will most likely lose their driving license for one or more years, be fined, and will have great difficulty in obtaining car insurance in the future.
"Many also risk losing their jobs or going to jail.
"The alternative consequences had they not been caught do not bear thinking about. Each one of these drink-drive detections has potentially saved lives."


Three prison officers suffered minor injuries after being attacked by inmates at Swansea Prison.

The Ministry of Justice said the incident on Friday 5 August lasted for around 15 minutes.
The prisoners involved have since been moved to other establishments.
A Prison Service spokesperson said they "do not tolerate any violence" against prison staff and were working with the police to push for the "strongest possible punishment".
The spokesperson added: "Safety in prisons is fundamental to the proper functioning of our justice system."


An allergy scare involving a three-year-old toddler has prompted Singapore Airlines to review the serving of nuts on board its flights.

Marcus Daley suffers from anaphylaxis, a potentially life-threatening condition which can be triggered by food including peanuts and shellfish.
He was travelling with his parents to Melbourne after a holiday in Thailand.
He suffered a severe allergic reaction after other passengers around him opened their snack packets of peanuts.
His father Chris Daley, a doctor specialising in respiratory issues, told the Australian Broadcast Corporation that his son received a special nut-free meal but quickly became severely ill when others were eating their nuts.
"He started vomiting, his eyes were starting to swell and he couldn't speak properly," Mr Daley said, adding that the family was less than an hour into their seven-hour flight home.
Thankfully, the Daleys had brought anti-allergy medication, which quickly brought the situation under control.
Major airlines such as Qantas, Air New Zealand and British Airways do not serve nuts during its flights or offer them in in-flight meals.
Singapore Airlines issued a statement on Wednesday saying it would review the serving of nuts on board all flights.
"As soon as our crew were made aware of the situation, they immediately removed all packets of peanuts from the area around the affected passenger and his family," the airline said.
"Our crew suspended the service of peanuts in the Economy class cabin for the remainder of the flight."
It added that passengers with nut allergies were able to request nut-free meals when making their flight bookings but said that they were not able to guarantee "a nut free cabin".
"We do not have any control over passengers consuming their own snacks or meals on board, which may contain nuts or their derivatives," the airline said in reply to a customer's comment on its Facebook page.
The incident has resulted in heated debate on social media, with many criticising the family's "irresponsible behaviour".
"They know the severity of their son's allergy and should have simply ensured he took the meds prior to the snacks being served," wrote Facebook user Melissa Chua, who described herself as a "frequent traveller".
"Nuts are one of the most common snacks served onboard. There are many people with nut allergies out there but you don't see them making such a fuss.
"Their sense of entitlement is so strong, to suggest an airline not serve nuts simply due to one passenger.
"When their son grows up, he'll have to learn that the world doesn't revolve around him."
Ali Fadli Mohd wrote: "Shouldn't their child have been given a mask to wear since he is so allergic? What if somebody brought peanuts along in their bag and opened it in the airplane?"
The online anger was overwhelming but some commented in support of the Daleys.
Yvonne Chua Kaiyin criticised "the lack of understanding" about such allergies.
"Because it occurs in an enclosed place, the boy can't escape it. His parents did bring his medication so they did prepare and they are responsible. Some people just don't understand."
Liz Ong, a mother of one, shared on Facebook: "My child has a life threatening food allergy. I am glad that this little boy survived the flight and I am so disappointed seeing these comments. We are responsible parents but no amount of medication can prevent an allergy in an enclosed space full of peanut dust circulating in the air during a flight.
"It may be a small inconvenience for you but I hope people will reconsider their decisions, to help keep a child safe."


Barbie is having a digital makeover, with the release of an internet-connected version of the iconic doll.

Toy maker Mattel is partnering with US start-up ToyTalk to develop Hello Barbie, which will have two-way conversations with children.
The Barbie will use a speech-recognition platform developed by ToyTalk.
A prototype of the doll was at the New York Toy Fair on 14 February, where a glut of smart toys were on display.
"The number one request we hear from girls around the world is that they want to have a conversation with Barbie. Now, for the first time ever, Barbie can have a two-way conversation," said a spokeswoman for Mattel.
The Hello Barbie will be able to play interactive games and tell stories and jokes.
It will also listen to the child's conversation and adapt to it over time - so, for instance, if a child mentions that they like to dance, the doll may refer to this in a future chat.
The doll requires a wi-fi connection and can provide an hour's worth of playtime when fully charged.
A microphone, speaker and two tricolour LEDs will be embedded in the doll's necklace, while rechargeable batteries in its legs can be connected to an external wall-mounted charger.
The doll is expected to sell for about $74.99 (Â£49). No release date has yet been confirmed.
Increasingly, the toy market is becoming saturated with smart versions of old favourites.
Back in November, the Vivid Toy group released Cayla, a doll that uses speech-recognition and Google's translation tools.
In January, security researcher Ken Munro discovered a vulnerability in its software, which allowed for it to be hacked to say things that might not be suitable for children.
A start-up, now live on Kickstarter, is developing a line of smart toys powered by the IBM-developed supercomputer Watson.
The first range from Elemental Path will be a smart dinosaur that can chat with children, tell them jokes and answer a range of questions.
"Toys have to keep up with the expectations of children," said Natasha Crookes, director of communications for the British Toy and Hobby Association.
"As long as children are protected from being able to access anything online, there is no harm in internet-connected toys.
"Companies take a lot of care making sure that there are white lists and black lists for content."
Some critics have questioned whether internet-connected toys endanger traditional, imaginative play, but Ms Crookes is not convinced.
"Such toys can enhance traditional play," she says.
"Some of the time, children will play with the toy in internet-connected mode, and some of the time they will play with them in the traditional way, using their imagination," she said.


The appointment of Pakistan's former army chief General Raheel Sharif to head a 39-country Saudi-led military alliance of Muslim countries to combat terrorism has set off intense debate in Pakistan and in the region.

The alliance is seen by many observers, but in particular by Shia Muslims in Pakistan and the Middle East, as a new Saudi-inspired Sunni block to counter Iran's growing influence among Shias in Syria, Iraq and Yemen.
After months of silence from Gen Sharif, Pakistan's defence ministry has now said that both Pakistan and Saudi Arabia have come to an agreement on his posting.
So far at least there does not seem to be an army made up of soldiers from any of these 39 countries and what exactly Gen Sharif will do in Saudi Arabia has not been disclosed.
But Pakistanis are anxious given that 20% of the population are Shia, there are large numbers of Shia officers and soldiers in the army - which has never faced sectarian unrest - and memories of the horrors of the 1980s when Saudi Arabia and Iran were accused of fighting a proxy war on Pakistani soil live on.
Each state, it was alleged, funded and supported militant Sunnis and Shia respectively in Pakistan to kill each other.
Even today there are still widespread attacks launched largely by Sunni militants against Shia across Pakistan and the government has so far failed to bring this sectarian war to an end. Many Shia have left the country.
The deal has prompted enormous debate in Pakistan, with the main opposition coming from Imran Khan's Tehreek-e-Insaf party, which says such a deal would worsen the Sunni-Shia rift in Pakistan.
The main advocate of the plan is Prime Minister Nawaz Sharif, who owes the Saudis several political debts, including his release from a jail sentence imposed a decade ago after he was toppled in a military coup. Mr Sharif then lived for many years in exile as a guest of the Saudis.
The army has also been historically close to the Saudis, providing troops and training in the 1980s to the Saudi armed forces and receiving help for the purchase of weapons systems.
Many Pakistanis are desperately keen that the country stay out of the crises that have gripped the Middle East.
Saudi Arabia and the United Arab Emirates are jointly trying to defeat the Houthi rebels in Yemen, who are Shia. The Saudis are also suspected of supporting a variety of militant Sunni groups fighting the regime of President Bashar al-Assad in Syria and of having helped Bahrain crack down on protests led by its majority Shia population.
Pakistan would like to avoid any involvement in these countries.
The Saudis have long asked Pakistan to contribute to its forces in Yemen, which so far Pakistan has refused to do. Last year Pakistan's parliament voted against sending Pakistani troops to Yemen. However the new Islamic alliance led by the Saudis and the appointment of Gen Sharif may alter the strategic picture for some.
Meanwhile Iran has increased its presence throughout the Middle East particularly in providing military aid to regimes in Iraq and Syria, while it is also allegedly helping the Houthis and other Shia in the region.
Iran has strongly objected to the appointment of Gen Sharif as head of the alliance. ''We are concerned that it may impact the unity of Islamic countries,'' said Iran's Ambassador to Pakistan Mehdi Honardoost on 4 April.
Islamabad insisted that it had told Iran of the appointment, but Tehran said that did not mean it had accepted the decision. Instead Iran has offered to help form a ''coalition of peace'' in the Middle East rather than forming a military alliance.
Raheel Sharif's acceptance of the job has led to intense debate on political talk shows on TV channels, with many people questioning why a very popular former army chief should now enter the quagmire of the Middle East, which may ultimately force Pakistan to make difficult strategic choices and almost certainly sour its relationship with Iran.
Much of the print media has been critical of the appointment, which has not been helped by the total blackout of information from both the government and the army as to what exactly this alliance hopes to achieve or how it will benefit Pakistan.
''The government is pursuing a course of action that undermines Pakistan's status as a neutral referee in the Muslim world,'' said Pakistan Today in an editorial.
Newly appointed Foreign Secretary Tehmina Janjua has pledged that Pakistan will maintain a balance in its relations with Tehran and Riyadh "even though it's very challenging".
There has been longstanding criticism from politicians and the media that Pakistan has been ignoring Iran, even though it is an important neighbour. So far Gen Sharif's appointment has only increased that criticism and created considerable unease as to the future course of Pakistan's foreign policy.


World number three Jordan Spieth shot a one-under-par 69 in testing conditions to take a two-shot lead after two rounds of The Open at Royal Birkdale.

Media playback is not supported on this device
The American, who finished on six under, had to contend with heavy rain, which caused a brief suspension, while gusting wind affected all the players.
Matt Kuchar (71), overnight leader with Spieth and Brooks Koepka, is second.
England's Ian Poulter (70) and US Open champion Koepka (72) are three under, with Rory McIlroy (68) on one under.
Northern Ireland's McIlroy, who was five over after six holes in round one, enjoyed the better of the weather on Friday morning with his two-under-par round putting him right into contention.
England's Richard Bland, 44, briefly tied for the lead on five under but was among the later starters who had to endure the worst of the weather and had three bogeys and a double bogey in his 72 to drop alongside McIlroy.
Media playback is not supported on this device
Scotland's Richie Ramsay is one shot better off after following his opening-round 68 with a 70.
Just eight players were able to post under-par rounds as the wind, which gusted up to 35mph on the Merseyside coast, proved ample defence for the course.
Nine players are left under par for the Championship, 26 fewer than after round one.
Media playback is not supported on this device
Two-time major winner Spieth began his round with a birdie on the first, before he was pegged back with bogeys on the third and ninth.
Successive birdies on the 11th and 12th holes were followed by a stunning eagle on the 15th as he opened a three-shot lead, despite heavy rain that left standing water on the greens.
However, he three-putted the 16th from 20 feet for a bogey but parred the final two holes to sign for a 69 to add to his first round 65 and tie for the lowest ever 36-hole score in an Open at Birkdale.
"I give myself a B grade today," said the 23-year-old. "I got pretty frustrated through the turn, hitting it into pot bunker after pot bunker and squeaking out pars somehow.
"I didn't get everything I could out of yesterday's round and I got more than what I deserved today."
Ominously it is the the third time he has opened a major with two rounds in the 60s, he won the Masters and US Open on the other two occasions.
Media playback is not supported on this device
Poulter, who began the day on three under, carded a solid 70 which included one bogey and one birdie.
The bogey came on the 16th and was his first in 26 holes.
"I have nothing to lose," sad Poulter, who finished runner-up at Birkdale in 2008. "I qualified to get in and I am going to try and go out there and grab it with two hands.
"I'm pumped up and ready to go out there toe-to-toe with anyone this weekend."
He added: "I'm pulling hard this week on memories of how I remember 2008."
Four-time major winner McIlroy knocked in three birdies in his first six holes on Friday to push him up the leaderboard, but the 2014 champion was pegged back with bogeys on the 13th and 15th, before a birdie on the 17th saw him under par at halfway.
He said: "To be in after two days and be under par for this championship after the way I started, I'm ecstatic with that."
McIlroy added that his second round was "right up there," with his best rounds at The Open.
"I couldn't ask to be in a better position after yesterday, having been five over through six yesterday and now be in the clubhouse after two rounds under par," he said.
Former Ryder Cup captain Colin Montgomerie said on BBC Radio 5 live that "anyone within 10 shots has a chance" heading into the final two rounds.
England's Paul Casey, who turned 40 on Friday, and had been in second place overnight on four under, is one player in that category, although he had seven bogeys in his 77 to finish on three over.
He sits alongside England's Andrew Johnston (74), world number one Dustin Johnson (72), Irish Open champion Jon Rahm (74) and Australia's Adam Scott (74).
Johnson, who bogeyed the last, after finding one of Birkdale's 123 bunkers, conceded: "I wish I could blame it on the wind. I'm just struggling a bit with the irons, not hitting the shots I wanted to."
Two-time champion Ernie Els (73) of South Africa was three over for the day to drop to one over alongside 2015 champion Zach Johnson, who shot the lowest round of the day with a four-under 66.
England's Ross Fisher's 72 saw him drop to two over, alongside Masters champion Sergio Garcia (69) and American Rickie Fowler (71).
Defending champion Henrik Stenson of Sweden is also two over after his 73, a day after his rental house was burgled while he played his first round.
Londoner Alfie Plant is guaranteed the silver medal, awarded to the leading amateur, because he is the only one to make the cut. The 25-year-old eagled the par-five 15th on his way to a 73 to add to his first round 71.
Plant has a 150-strong 'fan club' of family and friends wearing #TeamAlfie T-shirts following him round the course.
He said: "It's been brilliant. I hope the weather changes because I'm sure they'll be a lot louder."
When it was pointed out previous silver medal winners include Tiger Woods and McIlroy, Plant added: "That's not bad is it? Hopefully I'll follow in their footsteps."
Seventy-seven of the 156 players who started the Open have made the halfway cut - which is the top 70 players, plus ties and came at five over par.
Media playback is not supported on this device
A host of big names finished on that mark to make the weekend, with Olympic champion Justin Rose (74), former Masters champion Danny Willett (74) and fellow Englishmen Lee Westwood (74) and Tommy Fleetwood - who birdied the 15th and finished with three pars for a one-under 69.
Australia's Jason Day also sneaks in after the world number six shot a 76 along with two more Englishmen, Andy Sullivan and Toby Tree and Scotland's David Drysdale.
Former Open champion Phil Micklelson was one of the biggest casualties, missing the cut at The Open for just the fifth time in 24 starts, after a 77 left him on 10 over.
"The five-time major winner quipped: "Unfortunately it's the first cut I've missed this year and I missed it with flair."
Scotland's Martin Laird had five bogeys and two double bogeys in his 79 to fall to seven over, while 1999 champion Paul Lawrie (79) finished nine over.
Padraig Harrington, who won the Open the last time it was played at Birkdale missed the cut by one shot, while 2011 champion Darren Clarke also missed out.
Wales Stuart Manley who had been two under after the first round on his Open debut, had seven bogeys and three double bogeys to card an 11-over 81.


Police have launched an operation in the Chinese village of Wukan, to end protests over the jailing of the elected village chief.

Police, who entered the southern village overnight and raided homes, confirmed 13 people have been arrested.
Video posted online appears to show clashes in the streets with villagers throwing rocks at police who were using tear gas and rubber bullets.
Wukan now appears to be in lockdown and controlled by the authorities.
"Riot police are stationed at the entrance to our village. No-one can go in or out," one woman, surnamed Cai, told the BBC.
"I can't see any hope in this. The villagers feel so angry."
Police have accused villagers of spreading false information.
Lin Zuluan was voted in as Wukan's village chief in 2012, in an attempt by the local government to end months of protests about illegal land grabs.
He was jailed for three years last Thursday for corruption, but remains hugely popular. His supporters, who say a televised confession was forced and the charges are political, have been protesting again.
In the early hours of Tuesday morning, people inside Wukan began sending video footage to the media apparently showing police breaking into homes to arrest people.
In one video a man is seen being pinned to the ground by police in body armour, while other images show bloodied villagers.
The footage, which cannot be independently verified, also showed dozens of police under riot shields as protesters threw bricks and bottles.
A man with the surname Huang told the BBC that the government was trying to intimidate them into ending their protests.
He said those people arrested so far had assumed prominent roles in the protests or had been vocal on social media.
The local public security bureau in Lufeng, Guangdong has confirmed only that 13 people had been arrested for disturbing public order.
It said the villagers had "constantly spread rumours", forced others to protest and stopped people from working.
"Local government and police have been patiently warning them and educating them, but they turned a blind eye and completely ignored the laws," said the statement.
"In order to protect the interest of the public and return the village life to order, the police have taken action and arrested them."
Police later said some of those arrested had been charged with spreading "false information and old pictures to create the so-called 'Wukan incident'".
Wukan, with a population of about 13,000, had been seen as a model for possible political reform in China.
In 2011 its residents rose up in protest after Party officials began seizing and selling off their land.
In an attempt to stem months of protests, the government allowed them to hold elections for a new village chief, which were won by Lin Zuluan.
In early 2016, he began pushing again for the villagers to receive proper compensation for their land. But in June, he was arrested and charged with taking bribes.
On 8 September he was jailed for just over three years and fined 400,000 yuan ($60,000; Â£45,000).
The Global Times newspaper, seen as the mouthpiece of the ruling Communist Party, said on Tuesday that some of the seized land had been returned, but that some remained in dispute.


A Scottish parliament debate about tax has ended in stalemate after no party was able to win a majority of votes.

MSPs were talking tax ahead of the government's draft budget on Thursday.
The Tories put forward a motion opposing the SNP's plans, which would not replicate a UK government tax cut for high earners.
Amendments from all parties, including one from Finance Secretary Derek Mackay were rejected in a series of votes, before the motion itself also fell.
As a minority government, the SNP would need to win support from at least one party to back its budget.
However, there was no consensus on show at Holyrood following the tax debate.
There will be a formal vote on the government's tax proposals prior to the final vote on the budget in February, so both the tax plans and the budget itself will need to win backing.
Mr Mackay will set out his first budget on Thursday, and is expected to use new powers to draw a distinction between the tax regimes in Scotland and the rest of the UK.
This is because the Scottish government does not plan to replicate a tax cut for higher earners proposed by the UK government, via the raising of the threshold for the higher rate.
While the UK government plans to up the threshold for the 40p tax rate to £45,000 and eventually £50,000, the SNP has pledged to raise it by no more than the rate of inflation. This means some Scots will pay more tax than those earning the same amount south of the border.
The Tories said this would "make Scotland the highest-taxed part of the UK" - and, citing a report from chartered accountancy firm Johnston Carmichael, warn it may force firms to top up salaries of high earners affected by the changes.
Finance spokesman Murdo Fraser said: "The reality of the SNP's tax grab is that firms may end up having to pay high quality staff a 'Scottish supplement' simply to persuade them to stay and work here.
"What kind of message does that send out?
"As Johnston Carmichael make clear, if these costs get too high, many firms will conclude that they're better off moving to a part of the UK that actually welcomes employers - not one that punishes them.
"It is utterly self-defeating. The SNP claim the high moral ground, yet if enacted their policies will only end up starving our schools and hospitals of the tax revenues they need to survive."
Mr Fraser's motion for the Holyrood debate read "that the parliament believes business and families in Scotland should not be taxed more than those elsewhere in the UK".
He said the SNP had "lurched to the left" under Nicola Sturgeon, and said the SNP "has 24 hours to think again".
Mr Mackay put forward an amendment, arguing that powers were devolved so they could be used.
The finance secretary said: "The purpose of the devolution of powers over income tax is to allow Scotland to make its own decisions on tax rates. Powers over personal and business taxation should be used in a fair and progressive way that supports a sustainable economy."
He told MSPs: "The Tories are showing their true colours today. Not the tax position, but their position on devolution in Scotland. They have revered to type - do as Westminster does.
"They have reverted to type - London-controlled, tax cuts for the rich, abandon universal services and talk Scotland down. If divergence on tax is coming, it's because we want a different way for Scotland, and I'll be proud to propose that budget tomorrow."
Other opposition parties lodged amendments promoting their own tax policies, with Labour, the Lib Dems and the Greens all backing more radical schemes.
Labour's Kezia Dugdale said parliament should agree to a 50p top rate of tax for those earning over £150,000 a year, "so that the richest 1% pay their fair share to help stop the cuts and invest in public services".
She said Holyrood had "substantial powers" which meant it could make "different choices" to those made at Westminster, but said the Scottish government was guilty of just "tinkering around the edges".
Ms Dugdale said this meant any cuts to services resulting from Mr Mackay's budget would not be "trickling down" from the UK government, but would be "SNP cuts".
Lib Dem leader Willie Rennie also backed a tax increase, with his amendment reading: "Investing in skills is the best way to strengthen the economy, and calls for a modest penny on income tax for this purpose, raising £500 million to transform Scottish education."
He said Scottish education needed a "boost" in order to get back to being the best again, having been ranked "average" in recent international scores.
And Patrick Harvie from the Scottish Greens put forward an amendment saying "the SNP's manifesto proposals on tax make no significant changes to current income tax rates and thresholds", saying Holyrood should "support a tax system that will challenge inequalities in wealth and income".
He said it was "absurd" for the Tories to oppose there being different tax rates in Scotland and the rest of the UK, saying they were effectively arguing against the devolution of tax powers.
In the final votes, none of the amendments were passed, with Mr Mackay's falling by 61 votes to 60 before the others were all also defeated.
The motion itself was subsequently also rejected, by a vote of 92 to 29.


Music releases a chemical in the brain that has a key role in setting good moods, a study has suggested.

The study, reported in Nature Neuroscience, found that the chemical was released at moments of peak enjoyment.
Researchers from McGill University in Montreal said it was the first time that the chemical - called dopamine -  had been tested in response to music.
Dopamine increases in response to other stimuli such as food and money.
It is known to produce a feel-good state in response to certain tangible stimulants - from eating sweets to taking cocaine.
Dopamine is also associated with less tangible stimuli - such as being in love.
In this study, levels of dopamine were found to be up to 9% higher when volunteers were listening to music they enjoyed.
The report authors say it's significant in proving that humans obtain pleasure from music - an abstract reward - that is comparable with the pleasure obtained from more basic biological stimuli.
Music psychologist, Dr Vicky Williamson from Goldsmiths College, University of London welcomed the paper.  She said the research didn't answer why music was so important to humans - but proved that it was.
"This paper shows that music is inextricably linked with our deepest reward systems."
The study involved scanning the brains of eight volunteers over three sessions, using two different types of scan.
The relatively small sample had been narrowed down from an initial group of 217 people.
This was because the participants had to experience "chills" consistently, to the same piece of music, without diminishing on multiple listening or in different environments.
A type of nuclear medicine imaging called a PET scan was used for two sessions.  For one session, volunteers  listened to music that they highly enjoyed and during the other, they listened to music that they were neutral about.
In the third session the music alternated between enjoyed and neutral, while a functional magnetic resonance imaging, or fMRI scan was made.
Data gathered from the two different types of scans was then analysed and  researchers were able to estimate dopamine release.
Dopamine transmission was higher when the participants were listening to music they enjoyed.
A key element of the study was to measure the release of dopamine, when the participants were feeling their highest emotional response to the music.
To achieve this, researchers marked when participants felt a shiver down the spine of the sort that many people feel in response to a favourite piece of music.
This "chill" or "musical frisson" pinpointed when the volunteers were feeling maxim pleasure.
The scans showed increased endogenous dopamine transmission when the participants felt a "chill".  Conversely, when they were listening to music which did not produce a "chill", less dopamine was released.
Dopamine is a common neurotransmitter in the brain.  It is released in response to rewarding human activity and is linked to reinforcement and motivation - these include activities that are biologically significant such as eating and sex
Dr Robert Zatorre said: "We needed to be sure that we could find people who experienced chills very consistently and reliably.
"That is because once we put them in the scanner, if they did not get chills then we would have nothing to measure.
"The other factor that was important is that we wanted to eliminate any potential confound from verbal associations, so we used only instrumental music.
"This also eliminated many of the original sample of people because the music they brought in that gave them chills had lyrics."


Two Worcestershire hospitals which were closed to visitors earlier this month due to a norovirus outbreak have lifted visiting restrictions.

Alexandra Hospital in Redditch and Kidderminster Hospital have reopened to visitors, Worcestershire Acute Hospitals NHS Trust said.
Some restrictions remain in place at Worcestershire Royal Hospital, it said.
The acute stroke unit, Avon 3 and acute medical unit are still affected by the bug and remain closed to visitors.
"Patient safety is our priority, and we take any risk of infection very seriously, taking steps where necessary to prevent the spread of infection," chief nursing officer Lindsey Webb said.
"We are very aware of the impact visiting restrictions can have on patients and families.
"However, we took the difficult decision to close our sites to visitors as a way of preventing the spread of norovirus," she said.


Grateful Dead bassist Phil Lesh is being treated for bladder cancer in the US.

The guitarist made the announcement on the website for his restaurant in San Rafael, California.
He said he was diagnosed earlier this month and has been treated at a clinic in Arizona, where he will have surgery to remove his tumours.
The illness means Lesh has had to postpone his 24 and 25 October Phil & Friends shows with Chris Robinson.
The gigs with the former Black Crowes frontman were scheduled to take place at Lesh's restaurant, Terrapin Crossroads.
Lesh, 75, wrote: "I am very fortunate to have the pathology reports show that the tumours are all non-aggressive, and that there is no indication that they have spread."
He added that the postponed shows would be rescheduled "as soon as we can".
Lesh, one of the founding members of the Grateful Dead, was diagnosed with prostate cancer in 2006 but underwent surgery and made a full recovery.
The psychedelic band, which formed in 1965, split 30 years later following the death of frontman Jerry Garcia.
Lesh was with them throughout - and also joined the group's other surviving members for a reunion tour of the US in 2003.
The Grateful Dead performed their final shows in July this year, which also coincided with the 50th anniversary of the band's formation.
The gigs took place at Chicago's Soldier Field, which was also where Garcia's final show took place in 1995.


2016 was a year of change at the top in education with new ministers for schools and universities

But familiar problems over money remained.
Peter Weir became the first DUP education minister since the establishment of the assembly in 1998.
His party colleague and economic minister Simon Hamilton became universities minister as part of an expanded portfolio.
Mr Weir changed his predecessor John O'Dowd's policies in important areas like preparation for the transfer tests and GCSE grading.
However as the year ended he faced strike action from some of the teaching unions unhappy at a pay award of 0% for 2015/16 and 1% in 2016/17, although he disputed their figures and called their action "futile".
The Education Authority (EA) also faced pressures and will be forced to look for around £50m of savings in 2017, which will affect some front-line services to schools.
Moves by the EA to cut hours for pupils in special school nurseries were condemned by Mr O'Dowd in March, forcing them to apologise and to review their plans.
After taking over following the assembly election, Mr Weir reversed a long-standing departmental policy by allowing primary schools to prepare pupils for the AQE and GL Assessment tests.
He also initiated talks between the two test providers towards finding a common transfer test, but admitted he could not "impose" a single test.
In higher education, Mr Hamilton will continue to wrestle with demands from Queen's University and Ulster University (UU) for more money from either the public purse or from student tuition fees.
In a university document obtained by the BBC, Queen's said students should pay between £5,200 and £6,300 a year depending on the level of government funding available.
UU, for their part, warned in a report that they risked losing 20m euros (£17.5m) in European Union funding and tuition fees as a result of the Brexit vote.
However, a record number of Northern Irish students entered university in 2016 with 14,800 taking up places, according to the Universities and Colleges Admissions Service (UCAS).
And amidst concerns and controversies about money and the transfer procedure our education system still produces many successes.
The number of GCSE entries awarded A* to C grades in Northern Ireland increased by 0.4% to 79.1% in 2016, a rate well above that in England and Wales.
There were, as ever, some stunning individual results, while St Paul's High School in Bessbrook doubled the amount of "good" GCSE passes by boys in just two years by introducing a range of innovative measures.
The proportion of top A-level grades achieved by Northern Irish pupils also rose slightly.
However 15 students at Our Lady's Grammar School, in Newry, had their grades cancelled after being disqualified from an A-level sociology exam for alleged malpractice.
Northern Ireland had the highest-achieving primary school pupils in Europe in major international tests in maths.
The international rankings - Trends in International Maths and Science Study (TIMSS) - have been published every four years since 1995, and the latest results also ranked primary school pupils here as sixth in the world in the subject.
But while she noted a number of improvements, the chief inspector of schools said that too many pupils were still not getting a good enough education.
In her latest report, Noelle Buick also expressed concern over how children are taught here, pointing out that about one fifth of lessons were "less than good".
And with the possibility of more teachers' strikes in early 2017 and warnings by school leaders over the impact of stretched school budgets, Mr Weir faces a challenging start to the new year.


New students risk being blinded by deals - such as discounts on fashion brands - when choosing a bank account rather than guarding against debt.

Financial experts say most students would benefit from interest-free overdrafts ahead of any incentives that dominate marketing to freshers.
Students could find themselves paying over £150 a year extra in overdraft charges with some accounts.
Half of students struggle to make ends meet, according to the students' union.
Older students, those studying healthcare, and parents in education were most at risk of financial difficulties, the National Union of Students said. A "significant minority" turned to short-term, high-cost payday loans in order to cover expenses, it added.
Thousands of students are in the process of choosing a bank account ahead of the academic year. Banks are keen to sign them up owing to their future earning potential and possible long-term custom, so bombard them with money-off deals.
These range from rail and coach discount cards to cashback deals with major retailers.
"While these [deals] seem very attractive early on, the more useful perk for most students might be the size and length of the free overdraft on offer," said Brian Brown, head of insight at financial information service Defaqto.
He said that the incentives were less generous than they used to be, but teenagers were still inundated with mail and messages about these offers after they turned 18.
Andrew Hagger, of financial website Moneycomms, said: "The only freebie that may be worth a closer look is the free four-year 16-25 railcard from Santander which could save you plenty on your train fares, particularly if that's your chosen mode of transport between home and university.
"However, for most students, being able to borrow as much as possible interest-free will prove to be the biggest financial benefit."
Interest-free overdraft limits vary between banks, but they can also vary between students.
An overdraft is not guaranteed. Anyone wishing to borrow larger sums than an initial £500 or so may need to go through an application and will have checks on any credit history.
The limits on interest-free overdrafts vary between accounts and choosing between them may be time-consuming, according to Mr Brown.
"No product covers all the bases," he said. "The best approach is to decide which perks and features are most useful to you and then assess what is on offer rather than jumping on the first attractive perks at the freshers' fair."
That requires some planning - a task that many will be carrying out for the first time.
"Budgeting isn't fun or sexy but it is an essential life skill that can save you from worry, heartache and being clobbered with hefty bank charges," said Mr Hagger.
"Tapping out a quick spreadsheet on your laptop is all it takes to make sure you have a handle on your money matters and to know how much you have got in the bank to last you until the end of term."
A recent survey by NatWest Bank suggested that Edinburgh was the most expensive city in which to study in the UK. The most cost effective was Portsmouth, followed by Liverpool and Newcastle.
Irrespective of location, the NUS said that 50% of students struggled to cover day-to-day expenses. The problem was particularly acute near the end of term, and it called for student financial support to be paid monthly.
The most common reason that students gave for "seriously considering" leaving their course was financial difficulty, it said in its Pound in Your Pocket report.
"We would always recommend that students seek help from their university or students' union advice service if they think they are encountering problems," the NUS said.
"They will be able to check they are receiving all the support they are entitled to, can support students to access other forms of help such as hardship funds, or help negotiate with debtors if need be."
Other priorities when deciding which account to choose have changed with technology. The location of branches in a university or college town was a major consideration until fairly recently.
Now, access to modern payment methods is arguably more important for many of these young customers.
Mobile and online payment systems may make the task of regular payments, such as paying rent to landlords, easier, says Mr Brown.
Students looking to organise their finances may concentrate on their bank accounts, but insurance is an area that also requires their attention.
Cover for valuables was often overlooked, Mr Hagger said. Many university halls of residence include basic insurance in their fees.
Students may find that their parents' insurance policies already cover for some losses incurred while they are away.
Bikes are rarely covered under these policies so they may require further cover if they are valuable.
Insurance companies will need to be informed when a student takes their car to university or college with them, if living away from home.