The London Mayor Sadiq Khan has said on Friday afternoon there is “no reason to suspect foul play” amid the fire at the substation close to Heathrow Airport.
The fire closed Heathrow and some 1,300 flights were cancelled affecting tens of thousands of people globally.
Speaking at London Fire Brigade headquarters the Mayor said counter-terror police are investigating amid the close “proximity of the substation to the airport.”
Khan said, “When these sorts of incidents occur of this seriousness, they often declare a major incident.
“This was declared a major incident last night for obvious reasons, the proximity to Heathrow Airport and so forth.
“The fire service, the fire brigade, have been on the scene, they’ve been there since early this morning. They work really closely with the police service.
“Clearly because of the proximity of the substation to the airport it’s not a surprise the counter-terror teams been involved.
“The police service and the fire brigade will make sure that the public know whenever there’s any information to pass on to the public. But there’s no reason at all to suspect foul play at the moment.”
He added: “It’s one of the best airports in the world when it runs well. Clearly, today is going to be huge inconvenience to thousands of people, not just in London but across the globe.
“It’s really important the government is coordinating to support those passengers who are stranded. It’s really important those people who are going to leave today contact Heathrow or the airline about what the plans are.
“Heathrow is working really hard with National Grid to make sure things can return to normal as soon as possible.
“Clearly this will take some time for things to return to normal but it will be as soon as possible.”
A Downing Street spokesperson said on Friday, “The fire is still burning and I’m aware that the airport has announced a complete closure until midnight tonight as a result of the situation.
“It will be for emergency services and Heathrow to update on timescales for when this situation will be resolved. We do expect there will be significant direct disruption in the hours and days ahead.”