Martin Rolfe, Chief Executive of UK ATC provider Nats, was summoned to meet Transport Secretary Heidi Alexander on Wednesday (9 September) as the number of flights cancelled owing to a "technical issue" at the UK's ATC provider this week passed 2,000.

Nats disclosed the issue shortly before 1pm on Tuesday and traced it to its flight processing system. However, despite implementing a fix within hours, the knock-on effects of the outage has taken a huge toll on UK air traffic owing to limits on operations and displacement of aircraft.

"Our operations are stable and we continue to work closely with airlines and airports to support their recovery from the ongoing disruption to their operations," said Nats shortly before 1pm on Wednesday.

The Prime Minister's office, briefing national news reporters on Wednesday, indicated Rolfe retained its support, while tasking him with launching a delivering the findings of an investigation into the issue in a week's time.

According to aviation analytics firm Cirium, more than 1,700 flight movements – just over 30% of the 5,800 that were scheduled – were impacted on Tuesday, either being cancelled or not flying.

By 5.30pm on Wednesday, 357 of the 5,876 scheduled flights had been cancelled or did not fly, approximately 6%. On a normal day, this rate is between 1-2%.

Nats has apologised and promised a full investigation, while stressing its immediate focus is on managing flights. Rolfe also confirmed it was not the same system that failed over the August 2023 bank holiday weekend.

However, Ryanair has renewed its calls for Rolfe's head, claiming another review or report would be tantamount "to asking a failed student to mark their own exam paper".

"Martin Rolfe, after the August 2023 Nats system collapse, promised parliament that this wouldn’t happen again, and that an effective back-up system would be introduced," said Ryanair Chief Operating Officer Neal McMahon.

"UK passengers learned yesterday that these assurances were worthless. The Nats ATC system collapsed again, and yet again, there was no back-up system. Martin Rolfe cannot be trusted to report on his own failings."