An unspecified computer problem caused major disruptions to air traffic in the south east of England late Thursday, with flights delayed or cancelled at Gatwick, Heathrow and other airports.
The Central Flow Management Unit at Eurocontrol in Brussels told ZDNet.co.uk on Thursday afternoon that a "problem" was affecting flights.
"We understand that about half the aircraft supposed to fly into the [south-east] area can," said a Eurocontrol spokesperson. "We did have aircraft held on the ground."
A National Air Traffic Services (Nats) spokesperson told ZDNet.co.uk that "there was a failure in one of the systems that feeds the controller workstation in Swanwick air-traffic control at 3.55pm".
"Radar was not affected," the spokesperson added. "It was only in the London area. We imposed a zero-flow rate. We anticipate a return to full operations at 7pm at the moment." The spokesperson declined to say whether the problem was due to a hardware or software fault.
Eurocontrol's spokesperson said that, when Nats informed Eurocontrol of the issue, any flights on the ground were held on the ground, and any flights in the air continued to fly to their destinations.
ZDNet.co.uk blogger Matt Loney wrote on the site from Jersey Airport, where he said he had been informed that there had been a "failure of UK air-traffic control".
"We've heard it's a data-link problem affecting the south east, with the result that planes are taking off/landing every four or five minutes — way down on the usual 90 seconds," wrote Loney.