London’s Heathrow Airport closed on Friday after a fire at a nearby electrical substation caused a power outage, snarling travel for tens of thousands of passengers planning to fly in and out of Europe’s busiest airport.
A post on Heathrow Airport’s X account said the airport will be closed until 11.59 p.m. local time (7:59 ET) on Friday.
More than 600 flights were canceled in and out of the airport, according to flight-tracking site FlightAware as of Friday morning, upending travel at the major hub and connecting airport.
British Airways was the most affected airline, with over half of its Friday schedule canceled.
“Heathrow is experiencing a significant power outage across the airport. … Whilst fire crews are responding to the incident, we do not have clarity on when power may be reliably restored,” a Heathrow spokesperson said.
“We expect significant disruption over the coming days and passengers should not travel to the airport under any circumstances until the airport reopens,” the spokesperson said.
European travel and leisure stocks fell on the news.
Ed Miliband, U.K. energy minister, described the fire as “catastrophic,” according to Reuters, adding that the airport’s backup generator had been affected by the blaze.
Speaking to ITV’s “Good Morning Britain,” Miliband said the National Grid had told him the scale of the fire was unprecedented. “National Grid, in their conversation with me this morning, said it’s like a fire they’ve never, kind of, quite seen anything like the scale of what happened before,” according to a post by the program on X.
He said the National Grid was trying to use another backup system to restore power to the airport.
The cause of the fire is not yet known, according to Miliband, but foul play is not suspected.
Workers investigate the electrical substation following a fire at an electrical substation supplying power to the facility, in London, United Kingdom on March 21, 2025. The UK’s Heathrow Airport announced early Friday that it has been forced to close following a fire at an electrical substation supplying power to the facility. (Photo by Rasid Necati Aslim/Anadolu via Getty Images)
Rasid Necati Aslim | Anadolu | Getty Images
Power cuts also affected about 16,000 homes around the airport. As of 8 a.m. GMT, electrical supply was restored to all but around 4,900, according to the U.K. energy company Scottish and Southern Electricity Networks.
Canceled and diverted flights
More than 120 flights were already in the air when the closure was announced and were diverted or returned to their originating airports, according to Flightradar24. The flight-tracking site said 679 flights are scheduled to land, and 678 flights are scheduled to take off, from Heathrow today.
Some 145,000 passengers could be affected by the closure, according to aviation data firm Cirium.
Airlines around the world due to operate flights into and out of Heathrow and told passengers to stay home.
As the fire appears to be outside of the airlines’ control, they may not be required to cover compensation, according to a note issued by Citi on Friday.
‘It makes Heathrow look quite vulnerable’
Heathrow Airport has an estimated 1,300 take-offs and landings at the airport per day, according to its website. It handled a record 83.9 million passengers last year — a nearly 6% increase from 2023.
Speaking to “Good Morning Britain,” Miliband said on Friday: “We’ve got to understand why this happened, and we’ve got to work out what the lessons are for the resilience of our infrastructure.”
Firefighters douses flames of a fire that broke out at a substation supplying power to Heathrow Airport in Hayes, west London on March 21, 2025.
Benjamin Cremel | Afp | Getty Images
He said the National Grid is looking at whether there is “sufficient resilience” in place at the airport, given that the fire also affected a backup generator.
“It makes Heathrow look quite vulnerable. And therefore, we’ve got to learn lessons … about not just Heathrow, but how we protect our major infrastructure,” Miliband said.
‘Very wide’ implications
Anita Mendiratta, a travel and tourism advisor and founder of consultancy AM&A, described the implications of the fire and closure of the airport as “very wide.”
“What we also need to take into account is over and above passenger traffic, over 4,000 tons of cargo go through Heathrow every single day,” she told CNBC’s Squawk Box Europe.
More than 1.4 million tonnes of cargo flew in and out of Heathrow in 2023, according to a post on the airport’s website, with 90% of goods transported in the hold of passenger aircraft.
Airport officials said they will update travelers “when more information on the resumption of operations is available.”
Travelers can check Heathrow Airport’s website or social media platforms, including X, for the latest information.