The Metropolitan Police’s Counter Terrorism Command has taken over the investigation into the major fire at an electrical substation in Hayes, west London, which triggered a power outage at Heathrow Airport, causing widespread disruption to over 1,300 flights.

The blaze, which broke out around 11:30pm on Thursday (March 20), has been described as a “critical infrastructure incident” due to its impact on the UK’s busiest airport. Despite no confirmed signs of criminal intent, authorities say they are keeping an open mind as investigations continue.

‘Specialist Resources Required’ – Counter-Terrorism Takes Charge

In a statement, a Metropolitan Police spokesperson said:

“We are working with the London Fire Brigade to establish the cause of the fire, which remains under investigation. While there is currently no indication of foul play, we retain an open mind at this time.
Given the location of the substation and the impact this incident has had on critical national infrastructure, the Met’s Counter Terrorism Command is now leading enquiries.”

The spokesperson added that the command’s specialist resources and capabilities are essential to progressing the investigation quickly, minimising disruption and identifying the cause.

Massive Disruption to Flights and Financial Fallout

According to FlightRadar24, at least 1,351 flights to and from Heathrow have been affected, including 120 aircraft that were already in the air when the airport was abruptly shut.

Heathrow Airport, which saw 83.9 million passengers in 2024, typically handles around 200,000 passengers daily. The fallout from the fire has caused a major logistical and financial headache for airlines, airport authorities, and passengers alike.

Aviation consultant John Strickland said the financial cost to the industry will run into millions.

“You can’t quantify it yet, but there’s no doubt it will cost airlines dearly.
Follow-on costs like passenger rebooking, hotel accommodation, and refunds will mount rapidly. It’s unlikely these losses can be recovered.”

Speculation Over Cause Met with Caution

While the scale of the disruption has prompted speculation, Labour MP Ruth Cadbury, chairwoman of the Commons Transport Committee, urged caution.

“I think that’s somewhat speculative,” she told Times Radio, when asked if the fire may have been intentionally caused.
“There are obviously questions about it… but for the airport to be dependent on one substation, it does raise questions.”

Transformer Fire Involved 25,000 Litres of Oil

The London Fire Brigade confirmed the fire involved a transformer containing 25,000 litres of cooling oil, which posed significant hazards due to live high-voltage equipment and the intensity of the oil-fuelled flames.

Although the fire was brought under control by Friday morning, firefighters have remained at the scene, tackling hotspots, with about 10 per cent of the blaze still alight as of the latest update.

What Happens Next?

As Counter Terrorism Command continues its probe, focus remains on:

• Determining the exact cause of the fire
• Evaluating infrastructure vulnerabilities
• Minimising ongoing disruption at Heathrow
• Ensuring passenger safety and service recovery

Passengers are advised to continue checking with airlines for flight status updates and travel advice as airport operations gradually resume.

Would you like a follow-up feature on airport infrastructure resilience or a guide for passengers affected by Heathrow delays and cancellations?