The BBC Look North team tweet, external: Humberside Airport has been given no indication it will have extra traffic following closure of London Airspace, but prepared if necessary.

Phil Damerell tweets, external: Stuck on the runway at Heathrow en route to Berlin... but we have beer! And it's Christmas!

Image source, @Phil_Damerell

Heathrow Airport tweets, external: Check your flight status before coming to the airport. Flights experiencing severe disruption due to technical issue at air traffic control

Around 6,000 flights go in and out of the UK on a typical 24-hour period.

Image source, NATS

This video released by National Air Traffic Services last month gives a sense of how complex the picture is.

London Gatwick tweets, external: Flights are now departing from Gatwick but there are delays due to the Air Traffic Control computer issues.

Tom Edwards
Transport correspondent, London

This is unprecedented. I've never known anything like this.

Heathrow has a flight every 90 seconds so if you stop flights for an afternoon, it's going to have a huge impact.

The Nats press office tweets, external: We apologise for any current delays. Every possible action is being taken to resolve the situation.

London City Airport tweets, external: Update: No departures from LCY until further notice. Please contact your airline for info on your flight

Image source, Twitter

Tom Edwards
Transport correspondent, London

Sooner or later the queues will build up at Heathrow, Gatwick, Stansted and Luton.

Rebecca Cafe
BBC News

All flights are grounded while the airport awaits more information from Nats.

On average 450 flights go in and out of Stansted airport every day.

At the moment, 10 aircraft are waiting to depart.

Vicky Lane is at Gatwick Airport waiting to fly to Dublin.

She says: "We've been stuck on a Ryanair flight at Gatwick for over an hour. The doors are open and we're really cold.

"We're supposed to be flying to Dublin...I'm not sure when we will be leaving."

All departing flights have now been grounded at Gatwick, external.

Naomi R tweets, external: All the planes going nowhere #Heathrow

Image source, Naoimi R

Aberdeen Airport says: "An Air Traffic issue down south is having an impact on airport operations around the country this afternoon.

"In Aberdeen our advice is flights heading south will be affected until the issue resolves. Helis operating normally also. Contact your airline on specific flights."

BBC News Channel

Passenger Robert Bell, who was at Heathrow Airport awaiting his flight to Santiago, Chile, via Madrid, said: "We're at the gate and can see the tarmac and there's not a lot going on."

"We're in the dark," he added.

NATS: Airspace is open but restricted

Stansted Airport tweets, external: Due to a technical fault at NATS Swanwick ATC centre affecting London airspace, departing flights from @STN_Airport, external are currently suspended.

BBC News Channel

Aviation expert Chris Yates told the BBC News Channel: "There is a major failure at the London Air Traffic Control Centre, based in Hampshire, and we still don't know the reason for that failure."

Josephine McDermott
BBC News Online

Newcastle Airport, external is saying passengers should still come to the airport for their flights. Manchester Airport, external says the situation isn't affecting it at the moment.

Thanks to Anna who tweeted, external: @BBCLondonNews, external still seeing planes coming to Heathrow..

Image source, @thatswedishgirl

If you have any images or are affected by the closure of London's airspace please tweet @BBCLondonNews, external.