British Airways has grounded all flights from London's Heathrow and Gatwick airports because of “a major IT failure” that is causing severe disruption to its global operations.
The airline said Saturday that its terminals at the two airports had become “extremely congested” due to the computer problems, adding that all flights scheduled before 1700 GMT had been cancelled.
BA said there was no evidence the computer failure had been triggered by a cyber attack.
The global computer outage has created problems for tens of thousands of travelers on a key holiday weekend in Britain; the start of a Bank Holiday and the half-term break for some schools.
Heathrow said the IT problem had caused "some delays for passengers" and it was working with BA to resolve it.
Footage taken at the airport showed long lines at customer services after travelers were advised they would be unable to rebook because systems were down.
BA said it was trying to restore operations on Sunday, although some disruption to services would continue.
“We are working hard to get our customers who were due to fly today on to the next available flights over the course of the rest of the weekend. Those unable to fly will be offered a full refund,” it said.
The airline also said that the system failure had affected BA’s call centers and website.
Some passengers also complained that they could not check in on the airline’s mobile app.
The GMB trade union blamed the disruption on the airline’s decision last year to outsource some IT jobs to India.
“This could have all been avoided,” said GMB national aviation officer Mick Rix. “BA in 2016 made hundreds of dedicated and loyal IT staff redundant and outsourced the work to India.”
The airline said in response that it would “never compromise the integrity and security of our IT systems,” adding that outsourcing of IT services was a “very common practice across all industries.”