Passengers are facing widespread flight disruption after a computer failure at the UK's air traffic control centre.
Nats confirmed a "technical problem" at its Swanwick control centre in Hampshire and said airspace remained opened but restricted.
It said "every possible action" was being taken to resolve the issue.
Heathrow reported delays and Gatwick said all its departing flights had been grounded. Other UK airports reported knock-on effects.
They said:
- at Heathrow Airport flights are "currently experiencing delays" and planes could be turned away
- Incoming flights to Gatwick are continuing to land and all departing flights grounded
- Stansted say it is currently working with Nats to find out how it will affect the airpor
Manchester Airport said it was unaffected by the incident and was ready to accept diverted flights.
Vicky Lane, a passenger on a grounded London to Dublin plane at Gatwick said: "We've been stuck on a Ryanair flight... for over an hour.
"The doors are open and we're really cold. I'm not sure when we will be leaving."
-bbc
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