Hundreds of thousands of Britons may miss compensation after NATS flight chaos

Now, the British Civil Aviation Authority (CAA) has warned those affected by the disruption may not be in line for compensation.

"Although passengers should be looked after by airlines, they are unlikely to be entitled to compensation for delays or cancellations that were directly caused by the incident," it said in a statement.

Under UK law, passengers are entitled to compensation if a flight is significantly delayed or cancelled.

But the law has an exception for "extraordinary circumstances" which cannot be avoided - which the mass outage is likely to be.

Transport Secretary Heidi Alexander told MPs she did not believe the disruption was "unavoidable".

"We often take for granted the way in which our aviation system just works, but yesterday that was not the case," she said.

"Safety must remain air traffic controllers’ overriding priority, and this morning I have spoken to Nats chief executive Martin Rolfe, who informed me this outage was due to a technical issue at their Swanwick site.

"So, while my understanding from Nats is that we can rule out a cyber attack on this occasion, I do not believe this issue was unavoidable."

Ms Alexander has now requested the CAA conduct an independent investigation into the incident.

Shadow Transport Secretary Richard Holden said the disruption showed "just how important effective oversight is".

"The shocking failure of Nats has left hundreds of thousands of passengers in the lurch," he added.

Ryanair, which was forced to cancel over 200 flights, called on Mr Rolfe to resign and claimed the fault was "exactly the same issue" as in August 2023.

But Nats said the issue was not the same issue as it announced its own probe into the failure.

And, earlier on Wednesday, Downing Street said the Government still had confidence in Mr Rolfe.

According to aviation analytics firm Cirium, 2,145 flights have been affected over the last two days.

The worst affected airport was London Heathrow, which saw 79 out of a total of 666 departure flights affected.

EasyJet was the airline hit the hardest, with 31 of its 614 flights scheduled to depart on Wednesday affected.

British Airways said the fault had forced it to cancel almost 550 of its flights, which had impacted more than 85,000 passengers.

The airline said it was "incredibly sorry" to its customers and that the issue had been "entirely out of our control".

Travel disruptions have slowed and no flights are scheduled to be cancelled today.