Britain’s government and London’s Heathrow Airport have ordered looks into the handling of a power outage that shuttered Europe’s busiest air hub for almost a day as airlines warned of further delays and cancelations.

Britain’s energy ministry said on Saturday it had commissioned the National Energy System Operator to carry out an urgent investigation into the outage that raised questions about the resilience of the country’s critical infrastructure, Reuters reported.

Heathrow said it had tasked an independent board member, former transport minister Ruth Kelly, with undertaking a review of the airport’s crisis-management plan and its response to the incident with the aim of boosting resilience.

The airport said on X Sunday that it is “operating a full schedule again today, with over 1,300 flights planned,” but airlines are scrambling to make up for lost time. 

AIRLINES ISSUE TRAVEL WAIVERS DUE TO LONDON’S HEATHROW AIRPORT SHUTDOWN

Members of the Fire Brigade attend the scene following a major fire at an electrical substation at Heathrow on March 21, 2025 in London, England. (Leon Neal / Getty Images)

“Thank you for your patience following Friday’s closure due to an off-site power substation fire,” the post said. 

British Airways, whose main hub is Heathrow, promised a “near-full” schedule for Sunday after chief executive Sean Doyle on Friday warned the “huge impact” would last days.

LONDON’S HEATHROW AIRPORT TO REOPEN AFTER FIRE CAUSES POWER OUTAGE

Britain’s Heathrow airport, Europe’s busiest, was shut down early on March 21 for 24 hours after a major fire at an electricity substation cut power to the sprawling facility west of London, officials said. (BENJAMIN CREMEL/AFP / Getty Images)

Major airlines are waiving fare changes for travelers affected by Friday’s outage at London Heathrow Airport.

The airport is the world’s fifth busiest, according to Reuters. It was scheduled to handle 1,351 flights on Friday involving 291,000 passengers. However, the fire at a nearby electrical substation forced planes to be diverted to other airports and many long-haul flights returned to where they had departed from. 

A fire at the North Hyde Electricity Substation in Hayes prompted a massive power outage at London’s Heathrow Airport. (London Fire Brigade/Reuters / Reuters)

Police said that after an initial assessment they were not treating the incident as suspicious, although the investigation remains ongoing. 

London Fire Brigade said its investigations would focus on the electrical distribution equipment. Approximately 70 firefighters and 10 engines responded to the fire just before midnight on Thursday at the electrical substation on Nestles Avenue in Hayes.

CLICK HERE TO READ MORE ON FOX BUSINESS

“This was a very visible and significant incident, and our firefighters worked tirelessly in challenging conditions to bring the fire under control as swiftly as possible,” Assistant Commissioner Pat Goulbourne said in a statement.

FOX Business’ Elizabeth Pritchett, Greg Norman, Daniella Genovese and Reuters contributed to this report.