The airline says more than 50 of its flights have been cancelled, while over 65,000 passengers have been delayed by up to eight hours due to the Nats technical issue.

Ryanair criticises Nats for "yet another" system failure causing "widespread delays and cancellations across UK airspace", as it called for the CEO of Nats to quit.

It adds that despite "multiple investigations, reviews, promises and assurances that lessons had been learned, Nats' failures continue".

Nats says it has "identified" the issue and its "engineers are on site and working urgently to resume normal operations as quickly as possible", adding: "We recognise the ongoing disruption to travel, for which we sincerely apologise".

Rozina Sini
BBC Your Voice

Image source, Phil White

Phil White, from Bexhill, hoped to be in Lanzarote after boarding the 13:50 BST easyJet flight from London Gatwick, one of the airports experiencing disruption.

But he has been sitting on the plane for hours, with the plane unable to take off.

"We got on the plane in good time and we are still sitting on the tarmac," he tells the BBC, adding that it is "grim".

"We've been told the radar is down and we can't take off," he says.

"It's comfortable enough but the pilots have been on every 20 minutes saying they are waiting for information from air traffic control and when he finds anything out he will let us know."

• EasyJet has said some of its flights are "unable to operate" as a technical issue is affecting air traffic controller Nats

Around 200 flights have been cancelled this afternoon due to the UK air traffic control issue, and that number is expected to rise, according to flight monitoring site Flightradar24.

Air traffic controller Nats says the issue with its “flight processing system” is causing flight disruption across UK airports, adding that “recovery will take some time”.

Theo Leggett
Business correspondent

Departures from a number of airports in southern England, including Heathrow and Gatwick, have been affected by a technical problem affecting the air traffic control provider Nats.

At Heathrow, departures were initially paused around lunchtime. Traffic then resumed, before facing further stop-start disruption in the afternoon.

Incoming flights have been landing as normal. Gatwick said it was currently being affected by the issue, along with other airports.

In a statement, Nats said it was investigating an issue in its flight processing system, which it said was causing some disruption to flight departures.

Engineers were on site, it said, and it's "working urgently to resume normal operations as quickly as possible".

East Midlands has also been affected by the issue, while Manchester Airport warned that some departing flights could be delayed. Passengers have been advised to contact their airlines to check the status of their flights.

British Airways says like other airlines, it is "experiencing some disruption to flights as a result of a technical issue affecting air traffic control, which is run by National Air Traffic Control Services".

"This is entirely out of our control and we're in touch with our customers whilst our teams work to get them on their way as quickly as possible," it adds.

EasyJet says some of its flights are "unable to operate" following the technical issue affecting air traffic controller Nats.

"A Nats Air Traffic Control system failure this afternoon is unfortunately causing delays to flights across Europe with some flights unable to operate," the airline says in a statement.

The airline adds that it will do all it can to minimise the impact to customers, such as providing those on flights unable to operate with their options, including a free transfer or refund, and meals and hotel accommodation for those who require them.

Image source, EPA

Transport Secretary Heidi Alexander has posted saying she's "aware" of the technical issue.

"Technicians have identified the issue and are fixing it as we speak," she posts on X.

"I know this will be frustrating for passengers and I'm sorry. Please check with your airline for latest advice."

Flights departing the UK have been disrupted by an air traffic control "technical issue", the air traffic control group Nats says.

Nats says: "We are investigating a technical issue which is causing some disruption to flight departures.

"Our engineers are on site and we will provide an update as soon as we can.

"We apologise for the delay this will cause to journeys, passengers should check with their airline on the status of their flight."

This is a developing story - we'll have more details from airports and airlines soon.