Flights stopped ... Dozens of flights in the country’s busiest airports were being grounded. Picture: Ben Stansall/AFP Source: News Limited

Shortly after 3pm local time, the first of dozens of flights in the country’s busiest airports including Heathrow, Gatwick, Stansted, City and Luton were being grounded or ordered not to land due to the apparent computer failure. Flights further north in Leeds and Aberdeen were also restricted and within an hour other airports were also having to restrict take-offs.

As flights were being restricted at the major air hubs, flight paths from Europe particularly were chocked with aircraft trying to come into the country but unable to land due to the number of aircraft stranded on the tarmac unable to leave. Hundreds of flights were affected as they were either diverted to holding patterns or ordered to remain on tarmacs or parking bays.

Air traffic management company Eurocontrol said there had been “a failure” at a centre in southern England that was expected to last until 7pm local time. Air hubs moved quickly to apply to central authorities to authorise low level flying to allow some aircraft, particularly domestic, to move; that request was approved about an hour and a half after the chaos began.

Air chaos ... A screen shot taken from planefinder.net of aircraft approaching British airspace at 3:45pm GMT on Friday. Picture: AP Source: AP

Centre owners National Air Traffic Services (NATS) apologised for the failure at their state-of-the-art Swanwick Hampshire centre due to the power outage that caused computer aircraft tracking issues. It said in a statement: “UK airspace has not been closed, but airspace capacity has been restricted in order to manage the situation.” It added there had been a “measured recovery” by about 4pm, but the issue still caused severe delays expected to last into tomorrow.

There was a similar failure at the $1.2 billion centre this time last year although that took 12 hours to resolve and the schedules took a day to get back to normal.

At this point there has been more than 50 flights cancelled at Heathrow alone with more expected as the evening unfolds. The knock-on effect saw airports across the UK advise passengers there would be delays to all flights.

Airlines were Tweeting it was still too early to predict how many flights would be affected but warned while passengers should check in as normal, they should expect to be delayed for sometime.

Short haul flights into the UK from airports on the European continent were also being affected and were warning that despite issues in the UK now resolved, the impact to flights cancelled or delayed would continue into tomorrow local time. Those delays stem from aircraft not being where they should be to pick up or drop off passengers.