UK aviation was disrupted for more than four hours on 30 July 2025, due to technical air traffic control problems that affected operations at the country’s major airports in London and elsewhere.
While incoming flights continued, departing flights at Heathrow, Europe’s busiest airport, as well as Edinburgh, Gatwick, London City, and Newcastle, were grounded, affecting thousands of passengers just as they set out for much-needed breaks during the summer holiday peak season.
Even after schedules resumed, passengers were advised to check with their airline before commencing their journeys, due to the knock-on effect that any delays can have. Anyone whose journey has been affected should also check with airlines and insurers about their entitlement to compensation.
Flights have resumed at the UK's busiest airports after departures were grounded this afternoon because of a technical problem with air traffic control.
— Channel 4 News (@Channel4News) July 30, 2025
Thousands of flights were delayed before the system began returning to normal – as National Air Traffic Services said it was… pic.twitter.com/cv087n1eqD
The issue was “radar-related,” and centred on the National Air Traffic Services (NATS) provision based in Swanick. NATS, the UK’s main provider of air traffic management, told Reuters, it “was resolved by quickly switching to the back up system during which time we reduced traffic to ensure safety.” Shortly after a solution was found, NATS declared: “Departures at all airports have resumed and we are working with affected airlines and airports to clear the backlog safely. We apologise to everyone affected by this issue.”
But despite the outage only lasting four hours, the incident follows previous similar issues with NATS services over the last two years. In August 2023, again the height of summer, flights across the country were disrupted as a result of a malfunction with systems to automatically process flight plans. And in March 2025, a fire in a substation near Heathrow caused a complete loss of power part of the airport’s internal grid, shutting down flights for almost a day.
Travel industry experts estimate the closure of Heathrow alone could cost the sector at least £20 million pounds €23 million) a day, putting the cost of the latest four-hour closure there at £3.3 million (€3.8 million). That’s excluding the cost of closures at other major hubs around the country.
ℹ️Technical issue at Swanwick
— NATS (@NATS) July 30, 2025
As a result of a technical issue at NATS Swanwick air traffic control centre, we are limiting the number of aircraft flying in the London control area in order to ensure safety, which is always our first priority.
(1/3) pic.twitter.com/HzBYPGcq7M
The 2023 issue cost airlines well over £100 million (around €115.6 million) in passenger compensation and refunds, prompting fury from stakeholders. Although Britain’s aviation regulator, the Civil Aviation Authority (CAA), demanded a review of mandatory airport resilience plans, the repetition of technical problems has driven Ryanair to brand the situation “utterly unacceptable”.
The so-called “low-cost” carrier called for Martin Rolfe, NATS chief executive to step down, saying in a typically fiery statement: “no lessons have been learnt since the Aug ’23 NATS system outage and passengers continue to suffer as a result of Martin Rolfe’s incompetence.”
