Energy Secretary Ed Miliband has ordered the National Energy System Operator to “urgently investigate” the power outage caused by a substation fire, and is working with Ofgem and using powers under the Energy Act to formally launch the grid operator’s investigation.
Meanwhile, an internal review of the airport’s crisis management plans and its response to Friday’s power outage will be undertaken by former transport secretary Ruth Kelly, who is an independent member of Heathrow’s board, Heathrow chairman Lord Paul Deighton said.
A Heathrow spokesperson said the airport is expecting to operate a “full schedule of over 1,300 flights” on Sunday.
Investigation into Heathrow Airport power outage ordered
A statement said: “Today we will operate another full schedule of over 1,300 flights.
“We apologise for the inconvenience caused by our decision to close the airport on Friday following a significant fire at an off-site power sub station.
“Yesterday, we served more than 250,000 passengers, with punctual flights and almost all passengers waiting less than five minutes for security.”
The statement added: “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.
“While these inquiries are ongoing, our focus remains on serving our passengers.”
We’re operating a full schedule again today, with over 1,300 flights planned.
Thank you for your patience following Friday’s closure due to an off-site power substation fire. Yesterday, we welcomed 250,000+ passengers, with punctual departures and security queues under five… pic.twitter.com/loSWxBEKRQ
— Heathrow Airport (@HeathrowAirport) March 23, 2025
Flights were halted after a fire knocked out an electricity substation in Hayes on Thursday evening and were not able to resume until Friday evening. Restrictions on overnight flights were temporarily lifted after hours of closure.
Heathrow chief executive Thomas Woldbye said a back-up transformer failed during the power outage, meaning systems had to be closed in accordance with safety procedures so that power supplies could be restructured from two remaining substations to restore enough electricity to power what is described as a “mid-sized city”.
Counter-terrorism officers from the Metropolitan Police initially led the investigation, but the force said the fire is not believed to be suspicious so London Fire Brigade is now leading the probe which will focus on the electrical distribution equipment.
As he ordered the investigation on Saturday, Mr Miliband said: “We are determined to properly understand what happened and what lessons need to be learned.
“That is why, working with Ofgem, I have today commissioned the National Energy System Operator to carry out an investigation into this specific incident and to understand any wider lessons to be learned on energy resilience for critical national infrastructure, both now and in the future.
“The Government is determined to do everything it can to prevent a repeat of what happened at Heathrow.”
The National Energy System Operator (Neso) is expected to report to the Department for Energy Security and Net Zero and Ofgem with initial findings within six weeks.
Heathrow announced its own internal review on Saturday with Lord Deighton saying: “We are committed to finding any potential learnings from this unprecedented incident.
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“To fully understand what happened, I have asked Ruth Kelly, former secretary of state for transport and an independent member of Heathrow’s Board, to undertake a review.”
Thousands of homes were left without power and more than 100 people were evacuated after a transformer within the substation caught fire.
Heathrow is Europe’s largest airport, with more than 83.9 million passengers travelling through its terminals in 2024, and around 200,000 passengers have been affected by Friday’s closure.
