London's Heathrow Airport said on Wednesday operations were resuming after the control tower was briefly evacuated when a fire alarm was activated, although some flights would probably be delayed."We apologise for any inconvenience that this has caused," said a spokeswoman for Heathrow, Europe's busiest airport.
"Emergency services responded using our regular safety procedures, and our operations have started to resume."
National Air Traffic Services (NATS) said the control tower at the airport had been evacuated.
A spokeswoman said emergency services had attended and that flights would be returning to normal soon.