Power failure at Heathrow Airport sparks government investigation

A fire at a substation supplying power to Heathrow Airport led to major flight cancellations and disruptions on Friday, prompting the UK government to commission an urgent investigation.

The Department for Energy Security and Net Zero said the investigation will be conducted by the National Energy System Operator (NESO).

The review will assess the cause of the fire and examine the resilience of the UK’s energy infrastructure.

Energy Secretary Ed Miliband said the government aimed to understand both the incident and broader risks: “We are determined to properly understand what happened and what lessons need to be learned.”

Thousands of flights disrupted and passengers stranded worldwide

The power failure caused by the fire at the North Hyde substation in Hayes, west London, disrupted around 1,400 flights according to Flightradar24.

Approximately 120 flights were diverted and over 250,000 passengers were affected over the weekend.

On Saturday, Heathrow operated a full schedule with more than 1,300 flights.

However, the airport reported ongoing cancellations and delays.

More than 70 inbound flights and 30 outbound flights were cancelled that day.

Heathrow Airport said: “We have welcomed the Government’s announcement of an investigation into the cause and response to the off-airport power outage and have launched a review, to be chaired by former Transport Secretary Ruth Kelly, of Heathrow’s response.”

Substation and backup systems under scrutiny

The substation affected by the fire was one of three used by Heathrow.

Diesel generators and battery-powered systems were available to support critical functions like runway lighting, but were not sufficient to maintain full operations.

Heathrow CEO Thomas Woldbye told the BBC: “The incident was not created at Heathrow Airport, it was created outside the airport and we had to deal with the consequences.”

John Pettigrew, chief executive of National Grid, stated to the Financial Times that the airport could have accessed the remaining two substations.

“Losing a substation is a unique event — but there were two others available,” he said.

Official responses and resilience reviews underway

The investigation by NESO will report initial findings to Ofgem and the government within six weeks.

Cabinet Office Minister Pat McFadden is also leading a separate national resilience review.

Fintan Slye, NESO’s CEO, said: “We will now work with all relevant stakeholders to understand the lessons that can be learned to improve the future resilience of Great Britain’s energy system.”

Transport Secretary Heidi Alexander stated: “Heathrow is a massive airport that uses the energy of a small city, so it’s imperative we identify how this power failure happened and learn from this to ensure a vital piece of national infrastructure remains strong.”

Heathrow power outage: UK government to investigate airport shutdown after substation fire: Summary

On Friday 21 March 2025, a fire at the North Hyde electricity substation in west London caused a major power failure affecting Heathrow Airport.

The outage led to nearly 1,400 disrupted flights and stranded thousands of passengers worldwide.

The Department for Energy Security and Net Zero commissioned the National Energy System Operator (NESO) to conduct an investigation.

Initial findings are expected in six weeks.

Energy Secretary Ed Miliband said the government aims to identify any wider lessons on energy resilience for critical infrastructure.

More than 63,000 homes and around 150 people in nearby properties were also affected by the outage.

The Metropolitan Police said counter-terrorism officers were leading initial enquiries but were not treating the incident as suspicious.

Heathrow Airport announced a separate review chaired by former Transport Secretary Ruth Kelly.

NESO, launched in October 2023, manages electricity and gas network planning in Great Britain.

Ofgem stated it would take action if any licence obligations were breached.