Heathrow Airport returning to normal as investigations ordered into power outage
British Airways said it is expecting to run a "near-full schedule" on Sunday
Last updated 23rd Mar 2025
An investigation into the power outage caused by a substation fire that shut Heathrow has been ordered after about 200,000 passengers were affected by the airport's closure.
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.
British Airways said it is expecting to run a "near-full schedule" on Sunday and passengers should go to the west London airport as normal unless told otherwise.
The airline said it operated about 90% of its scheduled flights on Saturday when Heathrow said it was "open and fully operational".
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.
Akshay Kaul, director general for infrastructure at Ofgem, said it would "not hesitate to take action" if the review found any breaches of standards or licence obligations.
"Households and businesses should be able to have confidence in the resilience of critical national infrastructure, and Ofgem will work with the Government and others to ensure Neso's review goes as far as possible to ensuring steps are put in place to avoid any repeat of an incident of this scale in the future," he added.
Heathrow announced its own internal review on Saturday with Lord Deighton saying: "We are committed to finding any potential learnings from this unprecedented incident.
"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.
"The Kelly Review will analyse all of the relevant material concerning the robustness and execution of Heathrow's crisis management plans, the airport's response during the incident and how the airport recovered the operation with the objective of identifying any improvements that could be made to our future resilience."
Transport Secretary Heidi Alexander said: "It's imperative we identify how this power failure happened and learn from this to ensure a vital piece of national infrastructure remains strong."
She said "Heathrow, National Grid, and our emergency services have worked swiftly to get people travelling again" but added: "Whilst Heathrow is back to business, some disruption is expected over coming days as things get back to normal so I encourage anyone travelling to check with their airlines and plan their journeys."
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.
Chancellor Rachel Reeves has said the shutdown at Heathrow after a substation fire shows how important expanding airport capacity is.
"We do need to expand airport capacity in the UK and I think that what we've seen in the last couple of days has shown how important that is, but also how important it is to build the resilience in our UK critical infrastructure, including our hub airport Heathrow," she told Sky News'Sunday Morning with Trevor Phillips.
Asked if she regretted a decision to put off a second runway at Gatwick for six months, she said: "It's the first time that we've had an in-principle decision to expand Gatwick."