British Airways has cancelled all short-haul flights from Heathrow until midday and further disruption is expected throughout Saturday due to ongoing technical issues.
The airline said the problem, which may also cause delays for its customers using Gatwick and London City Airport, is related to a hardware issue and is not because of a cyber attack.
It said long-haul flights are still operating, but customers may experience some delays.
BA’s website and app were inaccessible for hours on Friday evening, preventing customers from checking in online or booking flights.
In a statement, BA said: “We are extremely sorry that due to the continuing technical issues we are facing we have regrettably had to cancel all short-haul flights from Heathrow today until midday.
“Customers due to travel later today should check their flight status on ba.com before coming to the airport as we anticipate further disruption during the day.
“Our long-haul services at Heathrow and all flights at Gatwick and London City Airport are due to operate as planned, but customers may experience some delays.
“Our website ba.com is working and customers can check-in online and at the airport.”
The airline said it will be contacting customers proactively, adding: “Our teams have been working hard through the night and will continue to do so to resolve the issue as soon as possible.
“We advise our customers due to travel today to check ba.com for the latest flight information before coming to the airport.
“We know we have let our customers down and we will do everything we can to make this up to them – but for now our focus is on getting as many customers and flights away as we can.”
Photographs of departure boards in Heathrow Terminal 5 showed few flights boarding, while people complained on social media about a lack of information.
Last summer BA settled a legal claim over a major data breach that affected 420,000 customers and staff.
The breach in 2018 included the leaking of names, addresses and card payment details and led to the Information Commissioner’s Office handing out a fine of £20 million.
On July 18 2018, computer problems hit BA operations at Heathrow and the airline cancelled a number of short-haul flights after the incident involving a “supplier IT system”.
In May 2017, 75,000 bank holiday travellers were stranded after a glitch forced the airline to cancel nearly 726 flights over three days.
The outage was suspected to have been caused by human error after an engineer disconnected and then reconnected a power supply to the data centre in an “uncontrolled and uncommanded fashion”.
Simon Calder, travel correspondent at The Independent, is in Qatar and is due to fly home overnight with BA.
He said: “British Airways, along with every other UK airline, invests a huge amount in safety and has an outstanding safety record.
“But with yet another weekend’s flying severely damaged by what BA calls ‘systems disruption’, the airline evidently has a pressing need to invest in IT.
“At a time when British Airways is still losing money at a prodigious rate, it can hardly afford to pay out tens of millions of pounds in recompense for its technical shortcomings. But that is exactly what the airline faces.
“Longer term, the reputational damage is rising with every cancellation. I calculate 1,500 passengers got up very early this morning to fly on British Airways from Heathrow to Geneva – and the same number waiting at the Swiss airport to come home. As with the thousands who have lost trips to Italy, the Canary Islands and beyond, they are unlikely to forget this weekend in a hurry.”
Paul Charles, chief executive of travel consultancy The PC Agency, said: “Ongoing technical issues don’t fill consumers with much confidence.
“Many people have saved up during lockdown to get away at the first opportunity and some are now finding that computers, not Covid, are preventing their getaway.
“BA needs to be transparent on what’s causing these issues and how soon they will be fixed.”