The first easyJet repatriation flights returning passengers to the UK following an air traffic control (ATC) fault will set off for London Gatwick as disruption continues.

The failure, which led to a spate of cancellations and delays, was caused by flight data received by National Air Traffic Services (Nats) – with both primary and back-up systems responding by suspending automatic processing.

Nats chief executive Martin Rolfe gave the explanation in a statement on Tuesday and made clear there are “no indications” the glitch was caused by a cyber-attack.

EasyJet announced it will run five repatriation flights to London Gatwick, with the first two set to take off on Wednesday.

The airline said: “During this traditionally very busy week for travel, options for returning to the UK are more limited on some routes and so easyJet will be operating five repatriation flights to London Gatwick over the coming days from Palma and Faro on August 30, and Tenerife and Enfidha on August 31 and from Rhodes on September 1.

“We are also operating larger aircraft on key routes including Faro, Ibiza, Dalaman and Tenerife to provide some additional 700 seats this week.”

Explaining the ATC fault, Mr Rolfe said: “Very occasionally technical issues occur that are complex and take longer to resolve.

“In the event of such an issue, our systems are designed to isolate the problem and prioritise continued safe air traffic control.

“This is what happened yesterday.

There are no indications that this was a cyber-attack

“At no point was UK airspace closed but the number of flights was significantly reduced.

“Initial investigations into the problem show it relates to some of the flight data we received.

“Our systems, both primary and the back-ups, responded by suspending automatic processing to ensure that no incorrect safety-related information could be presented to an air traffic controller or impact the rest of the air traffic system.

“There are no indications that this was a cyber-attack.”

Mr Rolfe added that Nats is working closely with the Civil Aviation Authority to provide a preliminary report to the Transport Secretary on Monday – the conclusions of which will be made public.

He also wanted to “reassure” people that all Nats systems have been running normally since Monday afternoon to support airline and airport operations.

The issue started on Monday, when more than a quarter of flights at UK airports were cancelled.

Nats suffered what it described as a “technical issue”, preventing it from automatically processing flight plans.

This resulted in flights to and from UK airports being restricted while the plans were checked manually.

Nats said at 3.15pm on Monday the problem was resolved, but disruption continued into Tuesday as many aircraft and crews were out of position.

Analysis of flight data websites by the PA news agency shows at least 281 flights – including departures and arrivals – were cancelled on Tuesday at the UK’s six busiest airports.

This consisted of 75 at Gatwick, 74 at Heathrow, 63 at Manchester, 28 at Stansted, 23 at Luton and 18 at Edinburgh.

Aviation analytics company Cirium said 790 departures and 785 arrivals were cancelled across all UK airports on Monday.

That was equivalent to around 27% of planned flights and means around a quarter of a million people were affected.