Almost 300,000 passengers could be directly impacted with the closure of Heathrow today (Friday) due to a nearby power outage.
The London hub – one the the busiest in Europe – is experiencing a “significant power outage” because of a fire at an electrical substation supplying the airport, a statement from Heathrow said.
“To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23:59 on 21 March,” the airport posted on X.
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“Passengers are advised not to travel to the airport and should contact their airline for further information. We apologise for the inconvenience.”
Numbers impacted
Aviation analytics firm Cirium estimated that airlines had been scheduled to operate 665 flights from Heathrow today, equating to more than 145,000 seats.
A further 669 flights were due to arrive, representing 145,836 seats.
For Saturday (March 22), there are 615 flights scheduled to depart from Heathrow, with 136,951 seats, while 604 flights are scheduled to depart from the airport, with 134,726 seats.
The biggest impact will be on Heathrow-based British Airways, with 341 flights to Heathrow scheduled, representing a potential 68,000 passengers.
Pointing to scheduled arrivals today, a Cirium statement said: “Roughly upwards of 145,000 passengers could be impacted. This is an estimate based on the daily total scheduled seats and flights, which will not be full, and noting the various departure times around the world that could arrive at LHR (Heathrow) on Friday.
“On the LHR departures front, upwards of 145,000 total seats are scheduled to fly on March 21. There are 669 flights scheduled to depart March 21, 2025.”
Some aircraft have been diverted to alternative airports including Gatwick, Paris, and Shannon in Ireland.
Due to a fire at an electrical substation supplying the airport, Heathrow is experiencing a significant power outage.
To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March.
Passengers are advised not to travel to the airport… pic.twitter.com/7SWNJP8ojd
— Heathrow Airport (@HeathrowAirport) March 21, 2025
Cirium data showed scores of inbound long-haul flights being diverted or returning to their point of departure involving BA, Virgin Atlantic, American Airlines, United, Delta, Air Canada, Air India, JetBlue, Japan Airlines and Qantas.
But the total closure will have knock-on effects on airline operations around the world.
British Airways has the largest share of flights from the airport (51%), followed by Virgin Atlantic and Lufthansa.
Flights diverted
BA is redirecting inbound flights already en route to Heathrow to other UK airports.
A BA spokesperson said: “Following the power outage that has caused the closure of London Heathrow Airport, we have had to cancel all short-haul flights that were due to operate to and from the airport today.
“Our teams are currently working hard to review our long-haul schedule as well as the implications for our schedule for tomorrow and beyond.
“We will update our customers as soon as possible and we continue to ask them not to travel to Heathrow Airport, but to check on ba.com for the latest flight information.”
Virgin Atlantic airborne flights are diverting to other airports in the UK or returning to their points of departure.
Passengers are being advised not to travel to Heathrow or their departure airport if Heathrow is their final destination.
Rebooking options are being explored and people with cancelled flights will be emailed with rebooking details.
A Virgin Atlantic spokesperson said: “We are aware of a fire at an electrical sub station near Heathrow airport, which has resulted in the airport’s temporary closure.
“Unfortunately this has had a significant impact on our flying programme both into and out of Heathrow and all Virgin Atlantic arriving and departing flights are cancelled until 6pm on 21 March, with the rest of today’s schedule currently under review.
“We kindly request that all customers do not travel to Heathrow or their scheduled departure airport, or contact our customer centre at this time and instead check their flight status at virginatlantic.com.”
The Guardian reported that Qantas had rerouted flights intended for Heathrow to Paris overnight, and planned to complete passengers’ journeys by bus.
Gatwick had accepted seven diverted flights originally scheduled to land at Heathrow by 5.30am this morning.
A Gatwick spokesperson said: “We are aware of the situation at Heathrow airport today and we are supporting by accepting diverted flights as required. Flights are operating from London Gatwick as normal today.”
Heathrow Express cancelled all services today and urged passengers not to attempt to travel to the airport “under any circumstances”.
Abta advice
An Abta spokesperson said: “If your flight is part of a package holiday – you will have the highest level of protections. Your travel company will be in touch regarding your holiday.”
Which? Travel editor Rory Boland warned: “This incident at Heathrow is set to cause major disruption for travellers, with reports suggesting the airport could be closed for the remainder of the day, and potentially longer.
“Don’t attempt to travel to the airport, but instead keep in touch with your airline for their advice.
“If your flight is cancelled you won’t be entitled to compensation as these events will be considered an extraordinary circumstance, but you will be entitled to assistance from your airline, including overnight accommodation if needed.
“Passengers will have the choice of being rerouted or accepting a refund, and if you opt for the former, your airline is obliged to get you on a new flight as soon as possible, including with rival carriers from alternative airports. If you instead accept a refund, be aware that your airline will have no further duty of care to you and you’ll need to make your own arrangements.
“It’s also worth checking the terms of your travel insurance to see if you are able to recoup any other expenses you may have incurred as a result of this incident, such as car hire or airport parking fees.”
Heathrow handled more than 5.7 million passengers in February, including a 7% rise in transatlantic traffic to the US and Canada.
Average daily passengers exceeded 200,000 for the 12th month in succession.
Heathrow reported a 6% year-on-year rise in passenger numbers in 2024 to reach a record 83.9 million from 79.2 million the previous year.
The fire at the substation in Hayes in west London left thousands of homes without power and caused around 150 people to be evacuated from surrounding properties.
Ten fire engines and around 70 firefighters were sent to tackle the blaze, the London Fire Brigade (LFB) said.
The cause of the fire remains unknown, the LFB said.
Assistant fire commissioner Pat Goulbourne said: “This will be a prolonged incident, with crews remaining on scene throughout the night. As we head into the morning, disruption is expected to increase, and we urge people to avoid the area wherever possible.”
National Grid said on X: “We are working at speed to restore power supplies as quickly as possible and will provide an update as soon as we can.”
Credit: Zotov Dmitrii/Shutterstock.com
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