A fire has caused the shutdown of Heathrow airport causing widespread travel disruption, including the diversion to Spain of a flight from Bermuda.

Counter-terrorism police are leading the investigation into the cause of the blaze at a West London electrical substation, which resulted in a power outage at Europe’s busiest airport.

A report on the British Broadcasting Corporation website said that Heathrow has warned of “days of disruption” with more than 1,350 flights expected to be affected today alone.

The Metropolitan Police, who serve the Greater London area, said that their counter-terrorism command was leading inquiries into the incident owing to the location of the fire.

It added: “This is due to the specialist resources and capabilities within that command that can assist in progressing this investigation at pace to minimise disruption and identify the cause.

“All possible lines of inquiry are being pursued and further updates will be provided in due course.”

British Airways said today that all short-haul flights that were scheduled to operate to and from Heathrow were cancelled, while long-haul services were under review.

A spokeswoman for Skyport said that several British Airways flights to and from Bermuda were impacted.

The BA159 yesterday was diverted to Madrid and was expected to arrive at Heathrow at about 7.18pm British time today, pending the airport’s opening.

Today’s, inbound BA159 and outbound BA158 were cancelled.

The spokeswoman said: “At this time, the next scheduled BA service is expected to operate on Sunday, March 23, in line with the regular schedule.

“Passengers are advised to contact BA directly for rebooking options and additional support.”

Stephen Davidson, a passenger affected by a cancellation, said: “BA are just overwhelmed right now in terms of trying to figure out what to do about it.

“Last night's flight and tonight's flight were full because of spring break.”

Lester Nelson, the chief executive of the Bermuda Airport Authority, said: “We are very sad to hear about the temporary closure of London’s Heathrow Airport, one of the world’s busiest, which will cause massive disruptions for passengers, LHR, airlines and other stakeholders.

“We understand that last evening’s British Airways Bermuda to London flight departed on time, but diverted to Madrid, Spain.

“There were no other disruptions at our airport.”

A BA spokesman said today that teams were working hard to review the airline’s long-haul schedule as well as implications for services tomorrow and beyond.

He added: “We will update our customers as soon as possible and we continue to ask them not to travel to Heathrow Airport, but to check on ba.com for the latest flight information.”

BA said it was contacting affected customers to offer options such as rebooking or refund.

It added: “We are also offering all customers booked to travel to or from Heathrow over the weekend — March 22 to March 23 — the option to rebook for free to a later date.

“We continue to ask customers not to travel to the airport but to check ba.com first.

“We’re advising affected customers to use the ‘manage my booking’ option to rebook their flight, rather than contacting our contact centres due to high call volumes at this time so our teams can help those with the most urgent requirements."

The BBC reported that Alice Delahunty, the head of Britain’s National Grid electricity transmission business, said the organisation was not in a position to rule out any cause of the fire at this stage, including an act of sabotage.

She said that the “very significant and serious incident” was “extraordinarily rare” across the network.