British Airways crew members arrive at terminal 5 at Heathrow on March 21, 2025 in London, England.
Peter Nicholls | Getty Images
London’s Heathrow Airport reopened Saturday but travellers are being warned of significant delays as airlines scramble to resume flights and return stranded passengers.
Europe’s busiest airport was closed for most of Friday after a power outage following a fire at a nearby electrical substation, causing over 800 flights to be canceled in and out of the airport, according to flight-tracking site FlightAware.
The first flight took off from the airport late Friday local time, however, and the airport’s departure board indicates that the majority of flights are due to run as scheduled on Saturday.
“Flights have resumed at Heathrow following yesterday’s power outage,” the airport said on its website Saturday.
“If you’re due to travel today, we advise you to still contact your airline for the latest flight information before heading to the airport. We apologise for the disruption and appreciate your patience whilst operations return to normal.”
National Grid said Saturday that power supply had been restored to all customers, including Heathrow, allowing operations to resume.
“We are now implementing measures to help further improve the resilience levels of our network,” the utility company said in a statement.
“We are deeply sorry for the disruption caused and are continuing to work closely with the Government, Heathrow and the police to understand the cause of the incident.”
London’s Metropolitan Police said that while there was “no indication of foul play,” the counterterrorism division would now lead the investigation into the fire.
“Given the location of the substation and the impact this incident has had on critical national infrastructure, the Met’s Counter Terrorism Command is now leading enquiries,” the force said in a post on X.
‘Expect delays’
Airlines are rushing to resume flights and get thousands of stranded passengers to their final destinations.
British Airways was the airline most affected by the incident, with over half of its Friday schedule canceled. It said it expects to run the majority of its Heathrow schedule on Saturday, but that customers should expect delays.
Ground crews load cargo and supplies onto airplanes from airlines including Lufthansa Group, Emirates, Austrian Airlines, and British Airways, as they stand parked at the Tom Bradley International Terminal (TBIT) at Los Angeles International Airport (LAX) in El Segundo, California, on September 11, 2023.
Patrick T. Fallon | Afp | Getty Images
“We anticipate that around 85% of our Saturday 22 March Heathrow schedule will run as planned, but to recover an operation of our size is extremely complex, so our customers will likely experience delays,” the airline said in a statement Saturday.
“We are advising customers to travel to the airport as normal unless told otherwise. If your flight is going to be disrupted, we will contact you as soon as possible to let you know what you need to do.”
It added that it was offering “flexible options” enabling those due to travel from Heathrow this weekend to rebook for a different date for free.
Heathrow Airport has an estimated 1,300 takeoffs 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.
The incident has raised questions over the dependence of the airport on a single power source.
Willie Walsh — former CEO of British Airways-owner IAG and now CEO of IATA, an airline industry group — criticized Heathrow Airport for its “total planning failure” and questioned who would cover the costs of the resulting disruptions.
“We must find a fairer allocation of passenger care costs than airlines alone picking up the tab when infrastructure fails,” he said. “Until that happens, Heathrow has very little incentive to improve.”