All London airspace has been closed.
A technical problem, thought to be a computer failure, has been reported at Swanwick Air Traffic Control centre, according to NATS:
“NATS can confirm that a technical problem has been reported at Swanwick air traffic control centre. We apologise for any delays and aour incident response team has been mobilised.
“Every possible action is being taken to assist in resolving the situation and to confirm the details.
“Further information will be released as it becomes available.”
London airspace is likely to remain closed until at least 7pm tonight.