A technical fault at the UK's air traffic control provider, NATS, brought Heathrow departures to a stop on Tuesday afternoon, 8 September, with knock-on delays expected to continue into the evening.
NATS said the problem originated in its flight processing system at the Swanwick control centre in Hampshire, which manages air traffic across southern England. Departures at Heathrow paused shortly after midday before resuming in a stop-start pattern through the afternoon, according to the BBC. Arriving flights were not affected.
"We have a technical problem at NATS Swanwick air traffic control centre which is causing some disruption to flight departures," a NATS spokesperson said. "Our engineers are on site investigating and we will provide an update as soon as we can."
Heathrow confirmed the disruption in its own statement, saying it was "supporting our local NATS team in their efforts to resolve the issue as quickly as possible," and advised passengers to check flight status with their airline before travelling.
The fault was not confined to Heathrow. Aberdeen, Edinburgh, Manchester, East Midlands, Birmingham, Bristol, London City, Stansted and Gatwick airports were also affected, according to Flightradar24 data reported by LBC, making this a UK-wide event rather than a Heathrow-specific failure. Flightradar24 said Eurocontrol was listing 8pm as the expected return to normal traffic across the affected airspace.