A server failure has forced the closure of all London airspace until at least 7pm, although airborne flights are able to land.
A note on The European Organisation for the Safety of Air Navigation website says that a faulty server has caused the problem.
“There has been a technical failure at London ACC. Engineers are working on the problem and more information will be given when available.
“Only already airborne traffic will be accepted.”
However, while incoming flights can land, space is quickly filling up due the amount of planes unable to leave the airport. This will likely mean planes will be diverted to other airports.
The UK Air Traffic Management service NATS said it had fixed the issue at 16:15, and hoped things would return to normal soon.
“Following a technical failure at Swanwick, the system has been restored and we are in the process of returning to normal operations. We apologise for any delays and the inconvenience this may have caused,” it said.
Heathrow Airport confirmed the incident on its Twitter account:
Flights are currently experiencing delays due to a power outage at NATS control centre affecting UK airspace. Further updates to follow.
— Heathrow Airport (@HeathrowAirport) December 12, 2014
Heathrow added in a statement: “There is a technical problem at the NATS control centre in Swanwick, which is affecting UK airspace. Flights are currently experiencing delays and we will update passengers as soon as we have more information.”
Gatwick Airport confirmed it was now seeing flights depart, although delays would last for several hours.
Flights are now departing from Gatwick but there are delays due to the Air Traffic Control computer issues.
— Gatwick Airport LGW (@Gatwick_Airport) December 12, 2014
The incident is likely to have severe repercussions for the stakeholders involved as it could lead to major financial charges from affected airlines and passengers.