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Hundreds of flights at Heathrow, Gatwick and other major UK airports were delayed or cancelled on Tuesday after a technical problem in the country’s air traffic control network triggered widespread disruption for departing services.
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Technical issue hits NATS and halts departures
Reports indicate that the disruption began early Tuesday afternoon, when air navigation service provider NATS experienced a system glitch affecting the management of departing traffic from some of the UK’s busiest hubs. According to publicly available information, Heathrow and Gatwick were among the first airports to pause or significantly slow departures while the fault was investigated.
Coverage from multiple outlets describes a technical issue in systems supporting air traffic control, leading to an immediate reduction in the number of aircraft that could safely be handled at any one time. As a result, departures were held at the gate or on taxiways, with some aircraft remaining on the ground for several hours as capacity was restricted. Heathrow and Gatwick both feature heavily in flight tracking data as experiencing concentrated clusters of grounded aircraft during the peak of the fault.
Specialist aviation reporting suggests that the problem did not affect radar or core safety systems but did limit the ability of controllers to process flight plans as normal. To maintain safety margins, the rate of departures was cut sharply, which had a rapid knock on effect at airports already operating close to capacity.
Scale of disruption across Heathrow, Gatwick and other hubs
Flight monitoring platforms show that hundreds of services were impacted across the UK network, with Heathrow and Gatwick bearing a significant share of the disruption. Data compiled during the afternoon indicated that around 100 flights had been cancelled at Heathrow alone, with hundreds more delayed by varying amounts as departure slots were pushed back repeatedly.
At Gatwick, live departure boards and tracking sites point to extensive late running, with some outbound flights delayed by several hours and inbound services held in queues or diverted to other airports once ground capacity became constrained. Other major airports, including Manchester and Stansted, also reported disruption as the national system bottleneck filtered through the wider schedule.
Analysis published by several outlets notes that, although the disruption originated in air traffic control systems, the overall number of affected flights grew as airlines were forced to rework rotations and aircraft positions. Cancellations started to climb through the afternoon as carriers concluded that some flights could no longer be operated within crew duty limits or available airport opening hours.
Passengers face long waits and uncertain connections
Passengers at Heathrow and Gatwick have reported lengthy waits in departure lounges and on board aircraft as crews awaited clearance to push back or take off. Images shared on social platforms show crowded terminals and departure boards dominated by delayed or cancelled statuses, with some travellers stating they had been advised to expect several hours of disruption.
According to published coverage, onward connections have been particularly hard hit, with passengers on multi leg journeys facing missed links and overnight stays. At hub airports such as Heathrow, where many travellers connect between long haul and short haul services, schedule gaps quickly cascaded into missed transfers once departure restrictions came into force.
Information available from airlines and airport websites stresses that travellers are being urged to monitor flight status pages closely and to arrive at the airport only if their flight is confirmed as operating. Travellers already in transit have been advised that rebooking options may be limited on some routes in the short term because aircraft and crews are out of position across the network.
Gradual recovery after fix implemented
By late afternoon, NATS stated publicly that a technical fix had been implemented and that systems were beginning to recover. Reports from aviation outlets and live flight data suggest that some departures at Heathrow and Gatwick started moving again once the restriction was eased, but with severely reduced resilience after several hours of disruption.
Industry analysts note that even a relatively short air traffic control outage can take many hours for airlines to work through, particularly at slot constrained airports such as Heathrow and Gatwick. The backlog of grounded aircraft, crew duty time limits and night curfews on arrivals and departures all limit how quickly normal schedules can be restored, especially on busy late summer travel days.
Public information from airports and airlines indicates that residual disruption is expected into the evening and potentially into Wednesday’s schedules, as aircraft and crew are repositioned and displaced passengers are accommodated on the first available services. Travellers with flights over the next 24 hours are being encouraged to check directly with their airline before setting off for the airport.
What travelers should do if they are affected
Consumer travel advice sites recommend that anyone booked to fly from Heathrow, Gatwick or other affected airports on Tuesday and Wednesday should first consult their airline’s app or website for real time updates. Rebooking and refund options are typically processed through official digital channels, which can be faster than queuing at airport desks during large scale disruption.
Passengers who are already at the airport are being advised, via publicly available information, to stay close to departure gates and pay attention to announcements in case of rapid re timings. Some airlines have indicated that they will prioritise departures for long haul and connectivity critical routes once additional air traffic slots become available, which could mean shorter regional flights are more likely to be retimed or cancelled.
Travel insurance policies may offer limited compensation for additional accommodation or expenses in certain circumstances, although coverage varies by provider and policy. Passenger rights under UK and European regulations can include care and assistance such as meals and hotel rooms during extended delays, even when the disruption arises from air traffic control issues rather than airline specific problems. Travellers are therefore advised to retain receipts and document communications with carriers in case they need to submit claims later.
Heathrow and Gatwick delays live coverage | Evening Standard
Air traffic control issue disrupts flights across UK | The Guardian
ATC issue disrupts flights at major UK airports | Reuters via Investing