UPDATE 1-Air traffic control problems causing delays at London Heathrow and Gatwick

Flights were being delayed at Britain's two busiest airports, London's Heathrow and Gatwick, following technical problems at the main air traffic control center for southern England on Friday.

The outage added to travel chaos in London, with commuter trains impacted by a summer heatwave and the Eurostar rail link to France halted by a power cable failure. "We have a technical problem with a system at the Swanwick Air Traffic Control which is causing some flight restrictions. We are doing all we can to fix it as soon as possible," Britain's NATS air traffic control service said.

Eurocontrol, NATS' pan-European equivalent, said the outage was causing a high level of delays at Heathrow and Gatwick, though they appeared to be easing. British Airways said it had been affected by severe weather conditions overnight as well as by the technical issue.

"We are doing everything we can to minimize the disruption, and our teams are working tirelessly to ensure as many of our customers as possible are able to depart on their trips," it said in a statement. "We have apologized to our customers, and are rebooking them onto alternative services or offering them hotel accommodation if necessary."

British Airways delayed taking delivery of its first Airbus A350 XWB, which had been due on Friday, in order to prioritize passenger flights.

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