Flights at Heathrow Airport slowly started resuming after 18 hours of disruption due to a fire at an electrical substation and the following power outage.

Media reports on Saturday cited a statement from Heathrow saying that it is "open and fully operational".

"Flights have resumed at Heathrow following yesterday’s power outage," the airport said in a post on X.

Authorities said they found no evidence that the fire was suspicious and the London Fire Brigade said the investigation would focus on the electrical distribution equipment at the substation.

 Britain's National Grid said it reconfigured the network around a substation and restored power to the parts of Heathrow Airport connected to it on an interim basis.

Heathrow, one of the world's busiest airports, was completely shut down after a large fire at a nearby electrical substation knocked out power on Thursday evening.

 

What has Heathrow Airport said?

On Friday afternoon, the airport said it was "now safely able to restart flights."

"Our teams have worked tirelessly since the incident to ensure a speedy recovery," the airport posted on X, the platform formerly known as Twitter.

"We hope to run a full operation tomorrow and will provide further information shortly," it said.

"Our priority remains the safety of our passengers and those working at the airport. We apologize for the inconvenience caused by this incident."

The London Fire Brigade earlier announced that the electricity substation fire that broke out Thursday night and shut down the airport was under control.

Earlier Friday, British Prime Minister Keir Starmer said in a social media post that he was receiving regular updates and that he was in close contact with partners on the ground.

Firefighters and police investigate cause of fire

Jonathan Smith, deputy commissioner of the London Fire Brigade, said the brigade was working with police to investigate the cause of the fire. 

Police said there was so far no indication of foul play in the blaze that shut down Heathrow, but counterterrorism detectives are leading the investigation into its cause.

Energy Secretary Ed Miliband called the fire at a substation that shut down London's Heathrow Airport "catastrophic" and said it also knocked out the hub's backup generator.

According to Willie Walsh, head of the airline industry's trade association IATA, a power outage that led to the complete closure of London's Heathrow Airport was a "clear planning failure" by the aviation hub.

"Firstly, how is it that critical infrastructure — of national and global importance — is totally dependent on a single power source without an alternative. If that is the case — as it seems — then it is a clear planning failure by the airport," IATA's Director General wrote on X.

Flights diverted worldwide

At least 1,350 flights to and from Heathrow were affected by the shutdown, according to the FlightRadar24 tracking service.

United Airlines said it expected its Friday departures to land Saturday morning at Heathrow. 

Heathrow handles more than 80 million passengers a year.

Transformer blaze to blame

Thousands of homes saw their power get knocked out and some 150 people were evacuated after a transformer at the North Hyde electrical substation caught fire in Hayes, around 6.5 kilometers (4 miles) from Heathrow.

The London Fire Brigade said 10 fire engines and around 70 firefighters were involved in fighting the blaze.

Footage posted to social media showed huge flames and large plumes of smoke coming from the facility.

Fire officials said they were called to the fire around 11.23 p.m. local time on Thursday.

Edited by: Sean Sinico