Alerting passengers, the Airport wrote on X: "Due to a fire at an electrical substation supplying the airport, Heathrow is experiencing a significant power outage."

The airport authority further said: "To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March. ."

The airport directed passengers not to travel to the facility and contact airlines for information on their flights.

"We apologise for the inconvenience," the X post said.

Staff Working To Solve

"Whilst fire crews are responding to the incident, we do not have clarity on when power may be reliably restored," a Heathrow spokesperson told BBC, adding that staff were "working as hard as possible to resolve the situation".

Hayes Substation Fire

Located in Hayes town in West London, the fire that broke out at the substation left thousands of homes without power.

According to local media reports, authorities have evacuated 150 people from properties located close to the substation.

Ten Fire Engines Operating

London Fire Brigade said ten fire engines and around 70 firefighters are working to douse the flame.

According to British media reports, over  16,300 homes are suffering power outages following the fire incident.

Energy supplier  Scottish and Southern Electricity Networks wrote on X: "There’s a fire at North Hyde substation in West London and emergency services are in attendance."

"The site has been evacuated and the safety of local residents, our colleagues, and the emergency teams is our highest priority. We will provide an update as soon as possible," the energy supplier said.

Meanwhile, the cause of the fire is still not known.

LFB Assistant Commissioner Pat Goulborne said firefighters are working tirelessly to bring the flames under control.

Goulbrone told BBC: "This will be a prolonged incident, with crews remaining on scene throughout the night."