At least 1,350 flights to and from Heathrow were affected, flight tracking service FlightRadar 24 said, and the impact was likely to last several days as passengers try to reschedule their travel

Some 120 flights were in the air when the closure was announced, with some turned around and others diverted to Gatwick Airport outside London, Charles de Gaulle Airport in Paris or Ireland's Shannon Airport, tracking services showed

The fire at a power station about 2 miles from the airport was brought under control about seven hours after it erupted in a ball of flames, the London Fire Brigade said

"We don't know the cause of this fire. It's obviously an unprecedented event," Energy Secretary Ed Miliband said

Miliband said the fire had also knocked out a backup generator supply to the airport. Heathrow said in a statement that the fire had given it no choice but to close the airport for the day

"We expect significant disruption over the coming days, and passengers should not travel to the airport under any circumstances until the airport reopens," the airport said

Heathrow is one of the world's busiest airports for international travel. It had its busiest January on record earlier this year, with more than 6.3 million passengers, up more than 5 per cent from the same period last year

January also was the 11th month in a row that it averaged over 200,000 passengers a day, with the airport citing trans-Atlantic travel as a key contributor

The disruption was reminiscent of 2023 delays that hit UK airports when Britain's air traffic control system was hit by a breakdown that slowed takeoffs and landings across the country on one of the busiest travel days of the year