Operations at London’s Heathrow Airport were brought to a halt early on Friday, 21 March 2025, after a fire at a nearby electricity substation led to a major power outage.
Heathrow Airport closed for the day: Here’s why
The blaze has forced the airport to shut down completely for the day, halting operations at one of the world’s busiest international aviation hubs.
According to Heathrow Airport officials, the closure will remain in place until 23:59.
In a public statement, the airport said:
“Due to a fire at an electrical substation supplying the airport, Heathrow is experiencing a significant power outage. To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March. Passengers are advised not to travel to the airport and should contact their airline for further information.”
At least 1,351 flights have been affected, with an estimated 145,000 passengers impacted by the shutdown.
The fire, which occurred in Hayes, prompted the deployment of 10 fire engines and 70 firefighters.
The London Fire Brigade confirmed the incident is ongoing and may take considerable time to resolve, describing it as a “prolonged incident” with continuing risks to surrounding residents.
The National Grid UK stated that the fire damaged key equipment at North Hyde substation, leading to widespread power failures affecting the airport and approximately 16,000 homes.
Emergency efforts to restore electricity are underway.
What happens to UK flights
With Heathrow closed, the effects on UK and global air traffic have been immediate and widespread.
According to flight tracking site Flightradar24, more than 120 in-air flights were diverted to other airports, including:
- London Gatwick
- Amsterdam Schiphol
- Paris Charles de Gaulle
- Dulles International Airport (Washington, DC)
- John F. Kennedy International Airport (New York)
- O’Hare International Airport (Chicago)
British Airways, which had 341 flights scheduled at Heathrow today, acknowledged “significant impact” and is working to rebook and update passengers. Virgin Atlantic has cancelled all Heathrow flights until midday.
Ian Petchenik, Director of Communications at Flightradar24, called the shutdown “extremely disruptive,” noting Heathrow’s role as a central hub for multiple global airlines.
He warned that it could take days or weeks for some carriers to fully restore operations.
With Heathrow typically operating at 99% capacity, the ripple effects of today’s shutdown are expected to affect not just the UK, but international schedules as well.
Travellers are advised to check directly with their airlines and avoid heading to the airport. Further updates will be issued as the situation develops.