
British Airways has promised a vast improvement in service at Heathrow and Gatwick after a global computer meltdown left thousands of passengers stranded ahead of the bank holiday weekend.

BA said a 'power supply issue' was the reason why all flights from the two airports were cancelled for the rest of the day, leaving droves of frustrated passengers scrambling for somewhere to stay.

Now it says the 'majority of flights' from Heathrow will be running on Sunday, while Gatwick will be operating at 'near normal' service.

Chief executive Alex Cruz said the crash affected all check-in and operational systems, adding: 'We believe the root cause was a power-supply issue and we have no evidence of any cyber attack.'

Earlier, the airline said flights would be running after 6pm - meaning passengers turning up for their evening journeys now face a mad scramble to book overnight hotel stays or organise transport back home.

Furious fliers around the world have been warned to expect days of chaos after enduring hours stuck in 'huge' check-in lines before being turned away.

BA operates hundreds of flights from the two London airports on a typical day - and both are major hubs for worldwide travel.

British Airways computer systems have crashed across the world ahead of the busy Bank holiday weekend, sparking mayhem at airports

Thousands of British Airways passengers are now scrambling for somewhere to stay after a global computer system crash left them stranded

BA said a 'power supply issue' was the reason why all flights from Heathrow and Gatwick were cancelled for the rest of the day

Stranded travellers pass the time at Heathrow Airport Terminal 5 after British Airways flights where cancelled at Heathrow Airport

BA said it was 'experiencing a global system outage' and told passengers not to travel to London airports on Saturday

Furious fliers across the UK, the US, Rome, Belfast and Lisbon - to name but a few - have been warned to expect days of chaos. Pictured: Stranded passengers waiting to

Many stranded passengers vented their fury online. Allison Sievers, from Colorado, wrote: Stuck on London tarmac for hours! Missed our connecting flight back home'

It is feared it could take days for services to return to normal and clear the backlog of passengers, many of whom have been demanding information on how to get reimbursed for flights, hotels and food.

Air industry consultant John Strickland said the crash would have a 'massive knock-on effect' for both customers and BA.

He said: 'From the airline's point of view, dealing with the backlog of aircraft out of position, parking spaces for the aircraft - it's a challenge and a choreographic nightmare.

He added that the problems with BA's IT systems last year were not on the scale of this issue, adding: 'They were bedding in a new check-in system last year and there were teething problem but not of the magnitude of this.

Parts of BA's website and app are not working and customers at Heathrow have been told it will take three hours to leave the airport - and they will not be able to get their bags today as the baggage system has broken down.

Several passengers reported that a captain and gate staff at Gatwick Airport said the airline could be under a cyber attack.

BA says it is working to restore services out of Heathrow and Gatwick by Sunday, though some disruptions are expected. It said London-bound long-haul flights are expected to land on schedule tomorrow.

Emily Wilson, an Australian student living in London who arrived at Heathrow at 11.30am to catch a 13.25pm flight to Stockholm, said passengers cannot get their baggage.

Air industry consultant John Strickland said the crash would have a 'massive knock-on effect' for both customers and BA

Several passengers reported that a captain and gate staff at Gatwick Airport said the airline could be under a cyber attack

Chief executive Alex Cruz said the crash affected all check-in and operational systems at BA terminals at Heathrow and Gatwick

Mr Cruz went on to say: 'We believe the root cause was a power-supply issue and we have no evidence of any cyber attack'

BA operates hundreds of flights from the two London airports on a typical day - and both are major hubs for worldwide travel

is feared it could take days for services to return to normal and clear the backlog of passengers, who are demanding answers from British Airways online

WHAT COMPENSATION ARE PASSENGERS DUE? In a letter to customers at Gatwick Airport the airline said it would be happy to 'consider' compensating passengers for meals, refreshments, hotels, and transport to and from their accommodation h'if an overnight stay is necessary'. They said the reimbursements would be as follows: - Hotel accommodation (£200 per day per room - 2 people sharing). - Transport between the airport and your hotel (£50 for the round trip). - Reasonable meal and refreshment expenses (£25 per adult per day and £12.50 for children). - Two reasonable telephone calls per customer. BA said it would be happy to 'consider' compensating passengers for meals, refreshments, hotels, and transport to and from their accommodation h'if an overnight stay is necessary' Citizens Advice Bureau claims passengers can request the following levels of compensation for delayed flights: - €250 for flights delayed three hours or more, where the flying distance is less than 1,500km - €400 for flights delayed three hours or more, where the flying distance is between 1,500km and 3,500km - or more than 1,500km within the EU - €300 for flights delayed between three and four hours - €600 for flights delayed more than four hours where the flying distance is more than 3,500km - or between an EU and non-EU airport €600 If your flight is delayed five hours or more, the airline legally has to give you all of the following: - A full refund for the flight - A full refund for other flights from the airline that you won't use in the same booking, eg an onward or return flight if you're part-way through a journey - A flight back to the airport you originally departed from food and drink - Access to phone calls and emails - Accommodation if you're delayed overnight, as well as journeys between the airport and the hotel Advertisement

She told MailOnline: 'They have told us it will take three hours to get out of the airport, and that we won't be able to get bags today. Their baggage system has broken down and the airline can't retrieve them.

Passenger Rhi Doherty, from Essex, said she was 'trapped' in Heathrow where staff had 'disappeared'.

'We have been stuck for over four hours, queuing to try and get out, we have been sent to wrong queues,' she said in a furious Instagram post this evening.

Rhi went on: 'All the computer systems are down. It's a security risk, there are police but we need more. They should have let young families out first to get away from the amount of people and heat but they didn't.

She also claimed that BA put a cap on compensations, with officials telling them they can 'only get a certain amount' and if they do not get their bags, 'we lose all of it'.

'All the BA staff have disappeared!' Rhi went on. ' It's absolutely awful here they have more or less abandoned us.'

Emily del Pizzo's family were forced to spend £2,800 on a flight to Venice after the surprise trip they had planned for months was ruined.

Passenger Rhi Doherty, from Essex, said she was 'trapped' in Heathrow where staff had 'disappeared'

Rhi also claimed that BA put a cap on compensations, with officials telling them they can 'only get a certain amount' and if they do not get their bags, 'we lose all of it'

Emily del Pizzo's family were forced to spend £2,800 on a flight to Venice after the surprise trip they had planned for months was ruined. Pictured: Stranded passengers out side Heathrow Terminal 5

She was only told about the destination when she turned up at Gatwick Airport with her husband Michael and sons Stefano, 13, and Nicola, nine.

'My husband is asking for an explanation from BA but unfortunately we are not getting anywhere,' she said. 'They are only telling us to go home and look online.

The family may now have to cancel the holiday, which had included Venice, trips to the seaside and to see relatives.

Saying she will never fly with BA again, she said: 'I do not think it is the way you should treat your customers, whether you spend £1 or £4,000.

'We have seen loads of people coming here and getting upset, just like us. Some people have spent a lot of money - and it is not about the money, it is about how you treat people.'

Passengers who need hotel accommodation were told to use a 'Pay and Claim' letter to claim back 'reasonable expenses', the airline said in a letter.

Check-in lanes at Heathrow Airport were flooded with hundreds of disgruntled passengers unable to get through due to the outage

Furious passengers are complaining of 'huge queues' at check-in and added that they cannot use the website or the app, causing them to miss their flights. Pictured, Heathrow Airport

Gareth Wharton, at Heathrow Terminal 5, tweeted a picture of BA staff writing gate information on a whiteboard amid the systems outage. 'Gets worse, T5 staff having to put gate info up on a white board,' he tweeted

The airline had said earlier in the day that flights would be running after 6pm - meaning passengers turning up for their evening journeys now face a mad scramble to book overnight hotel stays or organise transport back home

BA added that they were 'unable to predict' when the computer systems would be 'fully operational' and asked customers to leave the airport.

'There are children crying everywhere and so many crowds. It is really frustrating having been here all day,' Emily added.

'It's crazy for this to happen on bank holiday weekend. Our flights are not being rescheduled- we have to re-book online if we want new flights.

It's crazy for this to happen on bank holiday weekend. Our flights are not being rescheduled- we have to re-book online if we want new flights Stranded passenger, Emily Wilson

'We have received so many mixed messages. At first we heard anyone who had not checked in could not fly. Then we were sent through, and once arriving in the lounge we were told there could be a possible delay.

'Then news came out about all flights being cancelled but the staff had not heard about it. The manager came up eventually to announce official cancellation and said that we should leave and collect our bags.'

'Afterwards they started boarding some flights so everyone is very confused,' she added.'

She added that boards in Terminal 5 said that flights will be delayed until a certain time - although staff refuted this and said 'everything is cancelled'.

'There are people everywhere and we have been told to line up if we want to exit, and then we will have to clear customs before picking up bags.'

Furious fliers vented on social media that they have been stuck on their plane for more than two hours.

All BA flights from Heathrow and Gatwick have been cancelled for the rest of the day because of a 'major IT system failure' that is causing 'severe disruption worldwide'

Student Emily Wilson said that there were 'crowds everywhere and children were crying' as they waited at Heathrow Airport's Terminal 5 (pictured)

The airline has apologised and said it was 'working to resolve the the problem as quickly as possible'

One passenger shared this photo from their delayed flight, adding they were 'not allowed to buy food or drink'

A flier shared this photo from Terminal 5 at Heathrow Airport and wrote: 'Feel sorry for these guys, they've been on the plane for a couple of hours waiting to push back, due to the computer outage'

Passengers who need hotel accommodation were told to use a 'Pay and Claim' letter to claim back 'reasonable expenses', the airline said in a letter (left). A whiteboard (right) showed what gate passengers should head to

They spoke of 'disgraceful' customer service as staff gave out 'no information', while others said it was 'carnage' at Heathrow Airport's Terminal 5 and warned travellers to stay away.

A spokeswoman for the airline said: 'We have experienced a major IT system failure that is causing very severe disruption to our flight operations worldwide. We've found no evidence that it's a cyber attack.'

Travellers have been told to check the airline website and Twitter account for updates about the situation.

Stuck in Gatwick departures. BA have just announced that it could be a cyber attack that has taken down their systems Stranded passenger on Twitter

Several passengers said staff told them the delays were due to a hack - which BA denies.

'Gate agent at gate A10b just called it a cyber attack...true?' Bryan Henson said, while Michele Andjel added: ''It appears it is a cyber attack' said @British_Airways captain @Gatwick_Airport.'

'Stuck in Gatwick departures. BA have just announced that it could be a cyber attack that has taken down their systems,' another flier wrote on Twitter.

Heathrow Airport said it was 'working closely' with BA to solve the issue.

'The terminals at Heathrow and Gatwick have become extremely congested and we have cancelled all flights from Heathrow and Gatwick before 6pm UK time today, so please do not come to the airports,' the airline said.

'We are extremely sorry for the inconvenience this is causing our customers and we are working to resolve the situation as quickly as possible.'

The glitch has resulted in a crowd of tourists queuing inside the terminal, before eventually being turned away from the main British Airways terminal

Hundreds of bags have been left unattended as frustrated passengers queue for hours to leave the airport

Online check-in machines failed to work - with the screen saying it was 'temporarily out of service'

Emily Wilson, an Australian student living in London, shared photos of catastrophic queues at Heathrow

She told MailOnline: 'There are children crying everywhere and so many crowds. It is really frustrating having been here all day'

She said they received 'mixed messages' from staff and were eventually told they could not fly

A video she shared shows endless queues of people trailing all the way past the duty-free shops

They advised passengers to check the status of their flight before travelling to the airport.

Delays have also been reported in Rome, Prague, Cagliari in Italy, Stockholm and Malaga due to the technical failure and Gatwick Airport.

Several passengers at Heathrow said they had not been informed their flights had been cancelled until more than an hour after the airline put out a press statement announcing the decision.

Images posted to social media showed a group of people gathered around the customer services desk at Heathrow's Terminal 5 trying to get information.

Shortly after the statement was released, Terry Page, 28, from London, said: 'There's no such announcement here. The boards are showing 'Go to gate' and no mention of cancellations.'

More than an hour later, he said cancellations of individual flights were still being announced.

'They've announced them 30 minutes apart - I think to prevent panic and mass exit,' he suggested.

Mr Page, who was booked on a BA flight to Texas, was stuck in a queue in Terminal 5 for two hours.

He said: 'I tried to use their website to get a screenshot of my boarding pass - but the website isn't working either. (We) had to rely on the whisperings I could hear from staff talking,' he said.

One video posted by a traveller shows the captain (pictured) of flight BA553 from Rome to London addressing passengers about IT problems. He told the disgruntled crowds: 'There's just no way for anyone to depart a plane from anywhere in the world'

Fed up fliers flooded the terminals of Heathrow Airport as they waited in vain at their gate

One traveller said that it was 'carnage' at Heathrow Airport and warned others to stay away

Mr Page went on: 'We've tried all of the self check-in machines; none were working, apart from one. There was a huge queue for it and it later transpired that it didn't actually work, but you didn't discover that until you got to the front.'

'Then we queued for about an hour and a half with lots of people pushing in front to catch earlier flights.'

One video posted by a traveller shows the captain of flight BA553 from Rome to London addressing passengers about IT problems.

He told the disgruntled crowds: 'There's just no way for anyone to depart a plane from anywhere in the world.

'Those people who have been on a plane already are stuck on a plane and those people who have landed at Heahtrow are unable to get off because they can't park.

'So to be honest this is the place for you at this time.'

One passenger said: 'Systems down. Huge queues at check in. No explanation. Not good #britishairways #heathrowterminal.'

Passengers were also hit by severe delays in September and July last year because of IT glitches.

BA flights were also delayed on boards at Tegel Airport in Berlin

Several outraged fliers have been referring to the British Airways website to get compensation over the enduring delays

Passengers took to social media to complain about massive queues, adding that there was 'no explanation' from staff

Long list of failures: BA's history of technical glitches In September 2016 angry travellers complained of hours of queuing at airports after an IT glitch hit check-in systems. Travellers across the UK and U.S. complained of lengthy queues due to the technical problem, and passengers were warned of heavy delays. It is the latest in a series of technical glitches with BA's new 'FLY' check-in system which was rolled out in June in a bid to speed-up passengers' journeys. However, the system has been besieged by problems with five serious malfunctions in just three months causing huge delays to thousands of passengers around the globe. British Airways began installing its new system at airports across the world in October 2015and the roll-out was completed around June. BA, which is run by parent company IAG after it merged with Spanish giant Iberia in 2011, is in the process of cutting costs, including across its IT department. However, the new IT system has caused a host of problems with workers complaining that it crashes 'all the time'. One source claimed earlier this year that check-in staff have even been reduced to tears by regular glitches.ok The latest computer glitch is the fifth BA systems failure in just over three months, with similar problems on June 19, July 7, July 13 and again on July 18. Advertisement

Another added: 'Hey @British_Airways, couldn't log in to the app with my boarding pass on because systems were down and I missed my flight. What can I do?'

Nadia Whittley, added: 'British airways computers down T5 and standstill, stranded on the plane and they make us pay for food!! Please retweet this indicency! (SIC)'

Julie Adie wrote: 'We are on the runway.. For hour now..no offer of drinks..and because ba only takes cards now, we only have cash...wat we supposed to do!? (sic)'

Mr Tail, a 27-year-old teacher from London, claimed he had missed his flight to Rome because of the technical problems.

'I checked in online using the BA app at 8.15 for my flight at 9.25, then went and had breakfast,' he said.

'At some point the app restarted and when I went to go through security I couldn't log in to my booking to get my QR code.'

One traveller shared a photo showing massive check-in queues trailing out of Heathrow Airport's entrance

Outraged fliers vented that they had been stuck trying to check in or for their flights to take off for hours

Cyber attack on the NHS: How hackers took over computers and demanded cash not to wipe out patient records The NHS was hit with a crippling cyber attack in May, which saw patients turned away and operations cancelled. Hackers took control of computers in at least 40 NHS Trusts across the country meaning doctors could not access patients' files which are stored online. Messages popped up on computers which said 'oops, your files have been encrypted' and demanded a ransom of £230 to regain access to the PC otherwise the files would be wiped forever. One doctor at Colchester General Hospital said screens were 'wiped out one by one' while another described a matron running around frantically yelling: 'Turn off your computers'. British computer security expert Marcus Hutchins, 22, became a hero when he discovered the WannaCry super-virus had a 'kill switch' and stopped it infecting 100,000 more PCs worldwide over the weekend. The cyber criminals, who hit more than 225,000 victims in 150 countries in the biggest hack ever launched, then re-wrote their malware to remove the flaw discovered by Mr Hutchins. Britain's FBI - the National Crime Agency (NCA) - said people must be prepared for a 'second surge' of malware - but it is yet to happen on the scale seen on Friday. Rob Holmes, an expert from cyber security company Proofpoint, told the BBC: 'We're already starting to see new versions of the ransomware without the master kill switch'. Analysis by Elliptic, who have been tracking the Bitcoin accounts linked to the hackers, says they have been paid around $54,000 (£41,795) in ransom money since Friday. Advertisement

'This meant I couldn't go through security, and by the time I'd gone back and forth to various customer service desks the flight had closed,' he said.

'I've tried to call customer services but their systems are still down so they weren't able to help me, and they told me it was a worldwide issue,' he added.

Gareth Wharton, at Heathrow Terminal 5, tweeted a picture of BA staff writing gate information on a whiteboard amid the systems outage.

'Gets worse, T5 staff having to put gate info up on a white board,' he tweeted.

Melissa Davis, who runs MD Communications, a legal PR agency in London, was held for more than an hour and a half on the tarmac at Heathrow, on board a BA flight returning from Belfast.

Speaking from the plane, Miss Davis said the air conditioning had been off 'so I don't think we will be going anywhere any time soon', but added that the passengers had been kept informed by their pilot and given water while they remained seated.

She later said she and others were then told they could not transfer to other flights because 'they can't bring up our details'.

Earlier this month a 23-year-old appeared in court accused of costing BA £100,000 by taking its website offline for an hour.

Furious passengers are complaining of 'huge queues' at check-in and added that they cannot use the website or the app

Fliers stuck in the US, Rome, Belfast, Lisbon and from Heathrow Airport vented that they were had been waiting on their planes for more than two hours

Allegations of greed after BA outsourced IT jobs to India British Airways has outsourced IT jobs to India, leading to allegations of greed by unions. The GMB said the disruption could have been avoided if the airline had not cut 'hundreds of dedicated and loyal' IT staff and contracted the work to India in 2016. Mick Rix, national officer for aviation at the union, said: 'We can only feel genuinely sorry for the tens of thousands of passengers who are stranded at airports and face having their travel plans and holidays ruined. 'This could have all been avoided. In 2016 BA made hundreds of dedicated and loyal IT staff redundant and outsourced the work to India. 'BA have made substantial profits for a number of years, and many viewed the company's actions as just plain greedy.' The move in 2016 sparked protests and outrage from members of the union. At the time, a BA spokesman said: 'A contract has been signed with TCS to be the supplier of some IT activities in British Airways, and British Airways has been in consultation with those IT staff affected, about 200. 'British Airways employs around 35,000 people in the UK, providing high-skilled and well-paid jobs. It hires 1,000 people a year and has a strong apprenticeship programme.' Advertisement

Paul Dixon, of County Durham, was arrested after a cyber crime investigation led by the North East Regional Special Operations Unit in October 2014.

Dixon appeared before South Tyneside Magistrates' Court charged with five counts of carrying out unauthorised acts to impair the operation or access to a computer.

It comes as thousands of families had to fly off for half term without their luggage after Gatwick's baggage sorting system broke down – holding up 3,000 bags.

Their Bank Holiday weekend got off to a nightmare start as travellers encountered chaotic scenes and huge queues at Britain's second biggest airport.

The conveyor belt system that sorts bags before they arrive at the aircraft stopped working at around 5am yesterday, and was not fixed until around 9.15am.

Airline staff were forced to manually check each bag and put them on the right flight.Dozens of planes took off without all passengers' luggage on board.