Impact of Heathrow closure questioned after power supply failure

More than 1,300 flights were cancelled on 21 March 2025 after a fire damaged an electrical substation serving Heathrow Airport.

According to AP News, airport executives said the disruption lasted 18 hours and affected over 200,000 passengers, prompting criticism of Heathrow’s planning and operational response.

Heathrow said the incident required “hundreds of critical systems across the airport” to be “safely powered down and then safely and systematically rebooted”.

The International Air Transport Association (IATA) criticised the lack of redundancy in Heathrow’s infrastructure.

Willie Walsh, IATA’s Director General, said: “This is yet another case of Heathrow letting down both travellers and airlines. And that begs some serious questions.”

Power supply resilience under scrutiny

Heathrow’s management and the National Grid have disagreed over whether the airport could have remained operational using other substations.

John Pettigrew, National Grid’s chief executive, said to the Financial Times: “Each substation individually can provide enough power to Heathrow.”

He added: “Losing a substation is a unique event — but there were two others available. So that is a level of resilience.”

In contrast, Heathrow said its response was focused on safety and that operations resumed “as soon as safely and practically possible”.

Transport Secretary Heidi Alexander stated: “It required hundreds of systems to be safely powered down and then safely powered up with extensive testing.”

Police and security response to substation fire

The London Fire Brigade is leading the investigation into the incident.

Police initially treated the case with counterterrorism protocols due to heightened concerns about infrastructure sabotage across Europe.

However, authorities later confirmed there was “no indication of any foul play”.

MI6 has previously warned of sabotage risks linked to Russia.

Gareth Bacon, transport spokesperson for the Conservative Party, said in Parliament: “Malicious actors will undoubtedly have taken note of this weekend’s events.”

Decision-making process at Heathrow faces review

Questions have been raised regarding Heathrow’s internal decision-making during the incident.

Heathrow CEO Thomas Woldbye assigned the airport’s Chief Operating Officer, Javier Echave, to lead the response.

When asked about the leadership decisions, Transport Secretary Alexander said: “I don’t have all the information that they had available when they made the decision.”

She added: “Safety should always be paramount, but, as I say, it was not my decision.”

Government commissions urgent investigation into Heathrow incident

On 22 March 2025, the UK government formally launched an investigation into the Heathrow power outage.

Energy Secretary Ed Miliband commissioned the National Energy System Operator (NESO) to lead the inquiry under powers granted by the Energy Act.

The investigation will examine the causes of the outage and assess the resilience of energy systems supporting critical national infrastructure.

Miliband said: “That is why working with Ofgem, I have today commissioned the National Energy System Operator to carry out an investigation into this specific incident.”

Investigation to examine broader implications for energy security

NESO will work with Ofgem and other stakeholders, including Heathrow Airport, to assess the incident’s technical causes.

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

The terms of reference for the investigation will be agreed between NESO, Ofgem and the Department for Energy Security and Net Zero.

Initial findings are expected within six weeks.

Ongoing review part of wider UK energy resilience efforts

The Heathrow investigation forms part of the government’s broader “Plan for Change” to strengthen national infrastructure.

This plan includes the Cabinet Office’s resilience review, which is still underway and due to report in spring 2025.

Transport Secretary Alexander said: “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.”

Akshay Kaul, Director General for Infrastructure at Ofgem, said: “It’s important we now understand how that happened. Households and businesses should be able to have confidence in the resilience of critical national infrastructure.”

Regulatory oversight and enforcement powers

If the investigation identifies breaches of standards or licence obligations, Ofgem has stated it will consider taking enforcement action.

Kaul said: “To the extent the review finds any breaches of standards or licence obligations, we will not hesitate to take action.”

The findings will inform future steps to strengthen energy resilience and emergency response planning.

Further details of the investigation’s scope will be published in the coming days.

Heathrow power outage triggers UK infrastructure review: Summary

On 21 March 2025, a fire damaged one of three electrical substations serving Heathrow Airport.

The incident resulted in the cancellation of more than 1,300 flights and disrupted travel for over 200,000 passengers.

Heathrow said it safely rebooted systems after an 18-hour shutdown.

National Grid stated that the other two substations could supply sufficient power.

IATA criticised Heathrow’s planning and called for a fairer cost allocation.

Police ruled out foul play.

On 22 March, Energy Secretary Ed Miliband commissioned NESO to investigate the outage.

Ofgem and NESO will assess the technical causes and recommend improvements to energy resilience.

NESO’s initial findings are expected within six weeks.

The Cabinet Office’s broader resilience review is ongoing.

Ofgem has stated it will take enforcement action if any licence breaches are identified.

The investigation’s scope and terms will be published in coordination with the Department for Energy Security and Net Zero.