Passengers are being advised to ask their airlines for the latest updates for their flights today.
With major disruption at the airport, you might be wondering why this has happened and what has caused it – here’s what we know.
Why is Heathrow Airport closed?
Heathrow Airport is closed today due to a fire at a nearby electrical substation.
Thousands of homes have been left without power and more than 100 people were evacuated after a transformer within the North Hyde electrical substation caught fire in west London.
The airport, which is supplied by the substation, said it was among those impacted by the power outage.
Online flight tracking service FlightRadar24 said the closure would affect more than 1,350 flights to and from Heathrow. This includes 679 scheduled to land and 678 due to take off from the airport.
It said 120 flights to the airport were in the air when the closure was announced.
Heathrow is the UK’s largest airport, with more than 83.9 million passengers travelling through its terminals in 2024.
A Heathrow spokesperson said: “Heathrow is experiencing a significant power outage across the airport due to a large fire at a nearby electrical substation. Whilst fire crews are responding to the incident, we do not have clarity on when power may be reliably restored.
“To maintain the safety of our passengers and colleagues, we have no choice but to close Heathrow until 23h59 on 21 March 2025. We expect significant disruption over the coming days and passengers should not travel to the airport under any circumstances until the airport reopens.
“We will provide an update when more information on the resumption of operations is available. We know this will be disappointing for passengers and we want to reassure that we are working as hard as possible to resolve the situation.”
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… pic.twitter.com/7SWNJP8ojd
— Heathrow Airport (@HeathrowAirport) March 21, 2025
Some flights have been diverted to Gatwick, Charles de Gaulle Airport in Paris and Ireland’s Shannon Airport while others have turned around and returned to airports in the US and Canada as a result.
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When will Heathrow Airport reopen?
Heathrow Airport has been updating passengers on its social media channels this morning and it has shared when it believes the airport will reopen.
In a post on X, formerly Twitter, the airport said: “To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March.”
Therefore, flights are expected to be disrupted until then. The airport apologised “for the inconvenience.”
