The disruption affected several of the UK’s busiest airports, including Heathrow, Gatwick, Stansted and London City, as well as Manchester, Birmingham and airports in Scotland.

CNN Portugal reports that the problem was detected on Tuesday afternoon in the flight-processing system operated by National Air Traffic Services (NATS). The fault mainly affected departing aircraft, leaving some passengers waiting inside terminals or on board planes that were unable to take off.

NATS said its engineers had identified the problem and introduced a fix. However, flights did not immediately return to normal, as airports and airlines worked through the delays and repositioned aircraft and crews.

Flight-tracking service Flightradar24 recorded at least 250 cancellations during the disruption, while many other services were delayed. British Airways, easyJet, KLM and Lufthansa were among the airlines affected.

EasyJet said the failure had caused delays beyond the UK, with disruption spreading to flights elsewhere in Europe. Passengers travelling between Portugal and the UK could therefore also experience changes to their journeys.

Airports have advised travellers to check the latest information directly with their airline before leaving for the airport. Further delays and cancellations may continue while airlines deal with the backlog created by the system failure.

The incident has once again raised questions about the reliability of Britain’s air traffic control infrastructure. A major NATS system failure in August 2023 also caused widespread disruption, leaving thousands of passengers stranded and forcing airlines to cancel more than 1,500 flights.

NATS apologised to passengers and airlines affected by the latest problem and said the system was gradually recovering.