A 20-minute radar failure grounds departures across UK airports, triggering chaos and cancellations

A sudden radar failure at the UK’s air traffic control centre on Wednesday afternoon unleashed nationwide travel chaos, grounding planes and stranding passengers at major airports. The glitch triggered a 20-minute freeze on all departures, derailing more than 150 flights during one of the busiest weeks of summer.

The technical issue struck around 4 pm at National Air Traffic Services (NATS) in Hampshire. Although engineers switched to a backup system quickly, the disruption caused a cascading effect — leaving aircraft, crews, and passengers out of place and off-schedule.

Heathrow bore the brunt, recording 46 cancellations by the evening, including 29 outbound and 17 inbound flights. Gatwick and London City followed closely behind in cancellations and delays. In total, aviation analysts at Cirium confirmed 84 departures and 71 arrivals were cancelled across UK airports by 10 pm.

Flights mid-air were diverted or held in European cities. An Italian couple, attempting to reach Gatwick from Milan, ended up marooned in Paris for three hours. Valentina Balsarin and her partner Stefano were forced to wait on the runway while their connecting flight to New York ticked away. “Now, after three hours, we’ve been told we’re about to depart,” she said. “Even though I’ve lost my flight to New York.”

At Heathrow, passengers like Gurminder Marwaha sat idle for over an hour at the end of the runway. “The pilot said there was a delay. Fifteen minutes later, we were told there was a radar issue and no departures. They couldn’t give an ETA,” he recalled. “Eventually, they shut the engines and turned off the seatbelt signs.”

Fortunately for Marwaha, his flight managed to take off as the system resumed — others weren’t as lucky.

British Airways acknowledged “the vast majority” of its flights were affected. Until 7.15 pm, departures from Heathrow were limited to just 32 flights per hour — significantly lower than the standard 45.

The outage stirred fury among industry figures and politicians. Liberal Democrat leader Sir Ed Davey called for a full-scale investigation. “Air traffic control has once again been hit by a technical fault,” he said. “With thousands of families preparing to go on a well-earned break, this just isn’t good enough.”

Davey urged the government to determine whether the system was still fit for purpose and rule out any hostile involvement.

Meanwhile, Ryanair’s chief operating officer, Neal McMahon, went further — demanding the resignation of NATS chief executive Martin Rolfe. “It is outrageous that passengers are once again being hit with delays and disruption,” he fumed. “No lessons have been learnt since the system outage last August.”

In that previous failure, more than 700,000 passengers were affected — and many fear history may be repeating itself.

Transport officials maintained there was no cyber-attack. They confirmed that the radar systems are now fully operational and that flight flow has returned to normal levels. However, widespread delays remain, as airlines scramble to reposition aircraft and crews.

Passengers caught up in the chaos described a mixture of confusion and frustration. Some flights were abandoned with no notice. Others remained grounded without updates for hours, turning the travel experience into a waiting game.

As the dust begins to settle, questions loom over the resilience of the UK’s aviation infrastructure. How could a system so critical to national mobility collapse so suddenly? For the thousands of passengers still trying to reach their destinations, answers can’t come soon enough.