Heathrow has announced the cancellation of about 50 flights and expects the number will increase as the evening goes on. As Heathrow is a major hub for international transfers, the disruption is likely to be felt far beyond the UK. Over 67 million passengers travel through the airport annually on services offered by 90 airlines to over 180 destinations in more than 90 countries, according to its website.

Flights to and from London were severely disrupted on Friday by a technical failure at England’s main air traffic control centre that forced authorities to limit access to the country’s airspace.

“UK airspace has not been closed, but airspace capacity has been restricted in order to manage the situation,” the National Air Traffic Service (NATS) said on its website. It later said the system had been restored, but that it would take time for operations to fully return to normal.

Gatwick, another major London airport south of the capital, said flights were departing but with delays. Stansted airport, the city’s third busiest, said in a tweet that departing flights were also resuming.

Details on the cause of the problem were not immediately available. A government source, speaking on condition of anonymity, told Reuters it did not appear to be linked to any security threat to the United Kingdom,

Airports in Birmingham and Manchester, in central and northern England, said they were unaffected by the airspace closure and were ready to accept diverted flights.

British Airways said passengers who did not wish to travel on Friday could seek a full refund or postpone travel.

A spokesman at Stansted airport said: “All airlines have to refile their flight plans so there are bound to be delays, although we don’t know how long they will be,” said

A source at Heathrow, the UK’s biggest airport, said there “will be a lot of delays and cancellations. We have a lot of aircraft and crew out of position and crew are nearing the end of their shift.”

British Airways said it was working to look after all customers affected at Heathrow, Gatwick and London City. “We anticipate disruption to both departing and arriving aircraft but will do all we can to minimise any impact,” the airline said.

At Heathrow’s Terminal 5, there were motionless queues snaking around the departures area on Friday evening. Some passengers were waiting uncertainly in line for bag drop even when their flights had been cancelled. Many were slumped on the ground but the mood was calm

EasyJet said: “We are currently doing everything possible to understand the implications on our flight schedule for the remainder of the day. It is too early to say how many passengers and flights will be affected.”

London’s airports were forced to ground all departing flights during the current glitch to allow incoming flights to land. Stansted said it had accepted some flights diverted from London City while the restrictions were in place.

Swanwick

NATS said it suffered a technical problem at its air traffic control centre in Swanwick, southern England. Swanwick is one of NATS’ two main centres. The other is at Prestwick in Scotland.

Mikael Robertsson, co-founder of plane tracking site FlightRadar24, said it was very unusual for hundreds of flights to be diverted at the same time during the Friday afternoon travel peak.

Ian Allison, a computing science professor at Robert Gordon University in Aberdeen, said air traffic systems are usually designed to cope with technical failures.“So it seems to be a major incident that has caused the contingency plans to fail as well as the primary system,” he said.

NATS said the problem was related to “flight data communications” but that the cause was still under investigation. It said it was a different type of failure from one that hit Swanwick almost exactly a year ago.

The Swanwick centre controls aircraft travelling through 200,000 square miles of airspace over England and Wales and handles 5,000 flights in every 24-hour period.

It has been beset with problems since it first opened 12 years ago. The last major outage led to almost 300 flights being cancelled and 1,400 delayed over a two-day period.

That failure in December 2013 cost NATS £7.3m and led to the top executives losing part of their annual bonus.

Agencies

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