Air passengers have reported “carnage” as a fire closed London’s Heathrow Airport, cancelling at least 1,351 flights due to take off or land from Europe’s busiest airport.
The fire disrupted travel across the European Union, Heathrow’s largest market, and the facility was set to remain closed on March 21 until at least midnight.
An average of 77,000 passengers travel between Heathrow and the EU each day, a total of 28.1 million passengers in 2024.
Passengers were told not to travel to the airport “under any circumstances”, as the fire that began on the evening of March 20 continued to burn at the nearby North Hyde electrical substation at Hayes.
UK energy secretary Ed Miliband said the blaze was “unusual and unprecedented” and a back-up generator was “also affected by the fire”.
One US citizen in Ukraine posted on X that the fire had “all the hallmarks of [a] Russian sabotage operation this morning in London”, while another claimed it had “all the hallmarks of [the] UK’s crumbling infrastructure”.
All the hallmarks of Russian sabotage operation this morning in London, as 16,000 people are without electricity and Heathrow Airport is closed for at least a day, after an electrical substation has burned. pic.twitter.com/5syY0JPAz2
— Jay in Kyiv (@JayinKyiv) March 21, 2025
Effects on travel were “rippling” across Europe and beyond, with one traveller telling Sky News that “tempers [were] starting to fray” at Dubai airport.
When Heathrow announced it was closing, there were 120 aircraft in the air making their way to the airport, said airline website Flightradar24.
One transatlantic flight on American Airlines ended up in Bangor in Ireland, while an Air Canada flight from Toronto to London landed in Goose Bay, Newfoundland.
Ireland accommodated a half-dozen diverted flights, with the first arriving at 4:26am, Shannon Airport’s chief executive Mary Constance told RTÉ’s Morning Ireland.
The London Fire Brigade said in a statement that it had been called to respond to the substation fire at 11:23pm on March 20 and that the fire was “under control” by 6:28am as firefighters could be seen pouring foam on the substation.
Heathrow said it did “not have clarity” on when it would have its electricity restored. The local electricity distributor, Scottish and Southern Electricity Networks, said 4,900 local residents and businesses were without power.
The North Hyde transmission substation, which the National Grid owns and operates, takes electricity from the UK’s high-voltage electricity system and moves it into the lower-voltage distribution network that goes to businesses and homes.
Stranded passengers have seen prices rocket at hotels near Heathrow, with Holiday Inn charging £541 for a room for a single guest.
Ah here we go, hotels around Heathrow jump on the rip off bandwagon! This tonight’s prices at just 2. Typical rip off Britain and they should hang their heads in shame #r4today pic.twitter.com/b8BN2vHpkO
— Binman (@binman18691753) March 21, 2025
While the cause of the substation fire remained unclear, it “makes Heathrow look quite vulnerable” and it was necessary to “learn lessons” about “how we protect our major infrastructure”, Miliband told the Good Morning Britain programme.
“Aren’t you surprised that something as critical as the national airport is so very vulnerable?”, asked one astonished UK traveller on X.
Heathrow Airport is shut today because of a fire at an electrical substation.
Aren't you surprised that something as critical as the national airport is so very vulnerable? pic.twitter.com/hzzUcaoQmD
— Dave Sumner Smith (@davesumnersmith) March 21, 2025
⚠️ Power station near Heathrow in flames – and no, I don’t believe in coincidences.
A substation near London’s Heathrow Airport caught fire, shutting down one of the busiest airports in the world. Thousands of homes are now without electricity. The cause is “unknown,” but… pic.twitter.com/Ut4hxYx5QO
— Devana 🇺🇦 (@DevanaUkraine) March 21, 2025
