London’s airspace was restricted on Friday following a computer failure.
Britain demands investigation into cause of air traffic shutdown.
British officials called for an investigation into the roughly 35-minute shutdown Friday that severely disrupted air travel during the busy holiday travel season.
The shutdown prompted flight cancellations in London and other parts of Europe that officials said would spill over into Saturday, the Associated Press reported.
Britain's transportation secretary, Patrick McLoughlin, called the massive disruption "simply unacceptable" and asked for a full explanation.
The NATS center at Swanwick, which runs the air traffic system, has been plagued with software and reliability issues since opening 12 years ago at twice its anticipated cost and six years late, the AP reported.
Air traffic management company NATS clarified the situation just before 4pm on Friday.
Airspace is open. We're restricting traffic volumes in accordance with capability we currently have in our system.
The issue was blamed on a technical problem at the Swanwick air traffic control centre in Hampshire. A spokesperson said:
NATS can confirm that a technical problem has been reported at Swanwick air traffic control centre.
UK airspace has not been closed, but airspace capacity has been restricted in order to manage the situation. We apologise for any delays and our 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.
ITV reported that Manchester Airport has said it is prepared to take diverted flights due to the disruption.
The technical problem is expected to cause considerable delays, with a large number of flights grounded.
Heathrow airport is warning of "severe disruption".
Check your flight status before coming to the airport. Flights experiencing severe disruption due to technical issue at air traffic control
Stanstead said the all departing flights are currently grounded.
Due to a technical fault at NATS Swanwick ATC centre affecting London airspace, departing flights from @STN_Airport are currently suspended.
Gatwick said flights were departing but that there are delays.
Flights are now departing from Gatwick but there are delays due to the Air Traffic Control computer issues.
NATS has said its system has been restored and it is in the process of returning to normal operations.
System has been restored and we are in the process of returning to normal operations. For more information please see http://t.co/2ToleaTUrH