A military aircraft feeding “spurious” flight data into the UK’s air traffic control network is being cited as the likely trigger for Tuesday’s major aviation disruption, which brought large parts of the country’s skies to a standstill.
Around 2,000 flights to and from the UK were grounded after a four-hour technical failure at National Air Traffic Services (NATS), leaving more than 300,000 passengers facing cancellations, long delays and travel chaos.
According to sources, NATS operations director Kathryn Leahy told aviation industry leaders on a call later that evening that a flight plan filed by an aircraft — understood to be linked to the UK military — had set off the shutdown that disrupted Britain’s airspace for several hours.
The explanation reportedly stunned some industry figures, particularly because a similar breakdown in 2023 was traced to an unusual software fault in NATS’ flight processing system, the platform responsible for coordinating thousands of daily flight plans.
The Financial Times first reported details of the industry call.
Should the military flight data be confirmed as the root cause, pressure is expected to intensify on NATS chief executive Martin Rolfe. Industry sources said air traffic control systems should be capable of detecting and containing such problems before they spiral into the kind of nationwide crisis seen on Tuesday.
The fallout also left Labour facing mockery after it emerged that aviation minister Keir Mather had praised the UK air traffic control system’s “increased resilience” just one day before the failure.
Mr Mather said the system was “well prepared” following the introduction of new laws designed to avoid a repeat of the 2023 air traffic control meltdown.
His remarks were made on Monday in response to a written Parliamentary question uncovered by the Mail.
Within 24 hours, however, NATS suffered the four-hour technical outage that forced airlines to cancel more than 2,000 flights.
More than 330,000 passengers were affected over several days as carriers worked to restore schedules at major airports including Heathrow, Gatwick, Manchester and Stansted.
Mr Mather was appointed aviation minister last September at the age of 27, making him the youngest serving minister since William Gladstone in 1834, despite having no prior background in the aviation sector.
In the Parliamentary question, he was asked what steps had been taken ‘to reduce the risk of widespread flight disruption caused by air traffic control failures’.
A military aircraft entering ‘spurious’ flight data into the UK’s air traffic control system has been blamed for a meltdown which grounded thousands of planes
Aviation minister Keir Mather said air traffic control was ‘well prepared’ and had ‘increased resilience’ – just a day before Tuesday’s meltdown
Thousands of passengers were left stranded or delayed, with many sleeping on airport floors, during the fallout of the meltdown
He insisted 34 recommendations made in a review by regulator the Civil Aviation Authority (CAA) after the 2023 meltdown had all been implemented, adding that the aviation sector – including NATS – was ‘well prepared to respond to incidents when they occur in the future’.
He also boasted about new laws which came into force in December, making it easier for air traffic controllers to be recruited from other countries and the military, adding: ‘This will increase resilience in the UK’s Air Traffic Controllers system and reduce the risk of delays.’
But during Tuesday’s meltdown, NATS appeared to be no better prepared than the previous fiasco three years ago.
Tory shadow transport secretary Richard Holden said: ‘Labour are victims of their own supreme hubris.
‘Hundreds of thousands of passengers have been left on aircraft for hours, or faced cancelled and delayed flights because the supposed resilience Labour ministers talked up failed when it was needed most.
‘Labour ministers can’t have it both ways: if they boast about systems they created when they’re working they should take responsibility when they fail.’
Robert Jenrick, Reform UK’s Treasury spokesman, added: ‘Andy Burnham’s Government is proving just as incompetent as Keir Starmer’s.
‘This meltdown has cost billions of pounds and ruined the travel plans of thousands of passengers.
‘Why isn’t anyone being fired for yet another screw-up?’
NATS boss Martin Rolfe, who received £1.4million in pay and bonuses last year, has come under fire over the latest meltdown
Robert Jenrick, Reform UK’s Treasury spokesman, said Andy Burnham’s government is ‘proving just as incompetent as Keir Starmer’s’
NATS boss Martin Rolfe, who received £1.4million in pay and bonuses last year, has also come under fire over the latest meltdown.
He has faced growing calls to resign from his post after also presiding over the 2023 meltdown, which affected more than 250,000 passengers.
The August bank holiday failure that year was sparked when a small piece of incorrect data set off a mass system failure lasting just a few hours.
Another incident under Mr Rolfe’s leadership affected hundreds of flights in July last year and was blamed on a radar-related failure.
It was only a 20-minute outage but the knock-on effect caused some 250 flights to be cancelled.
The bosses of Ryanair and Wizz Air have been among those calling for Mr Rolfe to be sacked.
Transport Secretary Heidi Alexander ‘read him the riot act’, according to sources, after hauling him into Whitehall on Wednesday morning.
But she has dismissed calls for him to be sacked, instead giving him a week to compile a report into the fiasco to hand to her by Wednesday.
NATS, which serves 15 UK airports, has said the fiasco was sparked after its flight-processing system failed.
It has left thousands of travellers and holidaymakers out of pocket because the CAA said that under passenger rights rules, the issue is ‘likely to be considered the result of extraordinary circumstances’.
It added: ‘This means that although passengers should be looked after by airlines, they are unlikely to be entitled to compensation.’
The Department of Transport directed the Mail to comments made by Ms Alexander today while speaking to LBC, in which she said: ‘Earlier this year I was assured that all of those [CAA] recommendations were implemented.
‘The CAA produced reports in March and June of this year which I reviewed carefully but something has gone wrong here clearly.
‘We need to get to the bottom of it and you know I think it’s my responsibility as the Transport Secretary acting on behalf of passengers who will be rightly angry and frustrated, and the airlines, to make sure that I hold NATS and also the Civil Aviation Authority to account.’
NATS is a public-private partnership, with the government holding the controlling stake. The rest is split between a group of UK airlines including BA, easyJet and Virgin Atlantic as well as Heathrow and NATS staff.
A spokesman said: ‘The problem was fixed on Tuesday, and we are continuing to investigate the underlying cause. It would be wrong to speculate while that work continues, and a full technical investigation will follow.’
