British Airways could be facing huge compensation costs after thousands of passengers were stranded by a global IT crash.

Delayed travellers are able to claim compensation under EU law, unless the disruption has been caused by factors outside the airline’s control.

Air travel experts say BA is likely to face a massive cost in lost revenue and payouts to customers whose flights were cancelled.

Malcolm Ginsberg, editor in chief at Business Travel News, said: “There is no question – the EU denied-boarding regulations will have to apply.

“They have broken all the rules and they will have to deal with it – it’s going to be a very expensive situation for BA.”

Airlines also have to provide food and drink if their passengers are delayed by more than two hours under the regulations.

Civil Aviation Authority guidance states that anyone who is more than three hours delayed arriving at their destination could be entitled to compensation.

Meanwhile, the unprecedented disruption could last for several days, experts say.

Air industry consultant John Strickland said: “There’s a massive knock-on effect.

“Customers and from the airline’s point of view – manpower, 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.

“They were bedding in a new check-in system last year and there were teething problem but not of the magnitude of this,” Mr Strickland said.

The disruption has been compounded by the timing of the outage coinciding with a bank holiday weekend and school half-term holidays.

“Heathrow ordinarily would be busy but would be exacerbated by the bank holiday, half-term and Ascension Day, which is celebrated in a lot of Europe,” Mr Strickland added. “Even if they could quickly get the show back on the road, which is a big uncertainty, disruption could run into several days.”

Mr Ginsberg added: “This is a very, very serious situation, one that will not be solved overnight, even once they get the technology aspects of it done – it’s going to be three or four days. There’s only full aircraft at this time of year and there will be aircraft in the wrong positions.”