Rachel Clun, Faarea Masud & Tom Espiner
Business reporters, BBC News
Reuters
Airlines and airports expect some delays after the technical issue grounded all departures
Air passengers have suffered significant disruption after an air traffic control outage brought major UK airports to a standstill.
The technical problem was reported shortly before 17:00 BST and only lasted 20 minutes but caused a huge backlog of flights and delays.
Thousands of planes were grounded at airports including Heathrow, Stanstead, Manchester and Edinburgh. More than 120 flights to and from the UK were cancelled, as of 19:30.
Air traffic control firm NATS said the issue was “radar-related” and quickly resolved by switching to a back-up system, and it had reduced flight traffic to ensure safety.
It added there was no evidence the incident was cyber related.
The government said it was “working closely” with NATS to understand what had gone wrong.
It is the second time in two years that NATS has suffered a major outage.
The previous incident, which happened on the summer bank holiday weekend in August 2023, affected more than 700,000 customers.
NATS said the latest incident saw it limit the number of planes in the London area because of a “technical issue” at its Swanwick air traffic control centre in Hampshire.
It soon reported engineers had “restored the system that was affected”.
But many planes in the UK were grounded while the system was down, while others had to be diverted to different airports.
When departures resumed, NATS said it was “working with affected airlines and airports to clear the backlog safely”.
British Airways said it was still dealing with the impact.
“While this is entirely outside of our control, we want to apologise to our customers for any inconvenience and assure them that our teams are working hard to get their journeys back on track as quickly as possible,” the airline said.
Budget airline EasyJet advised customers travelling on Wednesday evening to check for up-to-date information on its flights, and it said it would contact affected customers directly.
A Heathrow spokesperson said: “We are advising passengers to check with their airline before travelling. We apologise for any inconvenience caused.”
NATS apologised to everyone affected by the issue.
Asha, 18, from Manchester, found herself “stuck” in an EasyJet plane on the tarmac at the city’s airport at 18:00 on Wednesday.
She said her “first holiday interrailing [has] gone wrong”
Asha had been on a 15:10 flight to Amsterdam that took off but was only in the air for 50 minutes before turning around.
Asha said some people on the flight wanted to get off the plane.
She was “hoping for some free food” to make up for the disruption.
One delayed passenger said the pilots were “as frustrated as everyone else”.
Robin Ilott, 62, from Waterlooville in Hampshire, said he’d faced a two-hour and 20 minute delay at Heathrow.
But he added: “It’s better safe than sorry, you don’t want to get up there and find that there’s planes everywhere.”
‘Outrageous outage’
Liberal Democrat leader Ed Davey called on the government to investigate the “utterly unacceptable” incident.
“With thousands of families preparing to go on a well earned break, this just isn’t good enough,” he said.
Ryanair chief operating officer Neal McMahon said “yet another” air traffic control system failure has “resulted in the closure of UK airspace meaning thousands of passengers travel plans have been disrupted”.
He said it was “outrageous” that the air traffic control issue has disrupted the plans of thousands of passengers, and called for NATS chief executive Martin Rolfe to resign.
According to flight data firm Cirium, as of 19:30, 67 departures and 55 arrivals had been cancelled across all UK airports.
In addition a number of flights had to be diverted to other airports, it said.
London Heathrow had the highest number of cancellations, a total of 24 departures and 14 arrivals so far.
Cirium does not attribute causes for cancellations, so some may not have been due to the air traffic outage.