Thousands of air travellers were hit by delays on Wednesday night at a number of UK airports after a computer glitch hit the National Air Traffic Services control centre.
Flights out of the UK were held on the ground after the computer problem struck at around 18:30(GMT). According to a spokesman from NATS the problem was resolved by 1903 and a spokeswoman for British Airports Authority told silicon.com the backlog of delayed flights had been cleared by around 2000.
The NATS spokesman told silicon.com: "We were handling in-bound flights the whole time and were able to start releasing outbound flight shortly after 1900."
He said the reason for the computer failure is not yet known.
"Establishing that is part of the investigation we have underway at the moment," he said.
Pilots posting comments on the Professional Pilots Rumour Network (PPRuNe) reported the glitch striking as some of them were already on the runway with passengers aboard.
"Happened at around 1900, just as our passengers were on board and we were ready to go! Was told that 'one of the computer systems is down at Swanwick [NATS control centre]'," wrote one.
This is the latest glitch to strike UK air traffic control. A worse outage in 2002 saw a number of flights cancelled as well as lengthy delays. That instance followed similar downtime the previous month.
NATS has proved a source of controversy as well as delays in recent years following its privatisation in 2001.