Flights in and out of Britain have been delayed by a computer failure at an air traffic control centre.
Most of the delays caused by the failure at the West Drayton centre in west London were at Stansted airport, north of the capital, and Manchester airport in northern England.
Two flights were cancelled and 30 delayed at Manchester Airport and international departures at Stansted Airport were delayed by up to three hours, a spokesman told CNN. The delays were expected to last until early afternoon.
A Heathrow airport spokesman told CNN a few flights at London`s main airport had been disrupted but that everything was back to normal by 8:00am (0700 GMT).
Gatwick airport, south of the capital, is not believed to have been affected by the computer failure.
The failure, which occurred at 6:00am (0500 GMT), meant flight data normally produced electronically had to be prepared by hand. Computers were down for 16 minutes.
Partly-privatised NATS, which is responsible for controlling the UK`s air traffic, has been hit by computer failures at its new centre in Swanwick in southern England. And in February it became a major embarrassment for the government when it said it urgently needed £30 million ($43 million) to maintain operations.
Seven airlines own a 46 percent stake in the NATS which the government partly privatised in July 2001.
The West Drayton centre has been running since 1972, but was made a fully modernised National Air Traffic Centre in 1996.
There are about 4,500 landings and takeoffs a day in Britain, 1,200 of them at Heathrow alone. Most are between the hours of 0600 GMT and 2000 GMT (1 a.m. and 3 p.m. EST).