According to flight-tracking website Flightradar24, at least 120 aircraft were en route to London’s Heathrow airport when the unexpected closure of the airport was announced on March 21st 2025.

A significant fire at the North Hyde electrical substation in Hayes, West London, led to a power outage at London Heathrow and subsequent all-day closure. The blaze engulfed the electrical sub-station at around 23:30 GMT (March 20), which required over 70 firefighters to bring it under control.

The sudden closure of Heathrow, Europe’s busiest airport, disrupted over 1,300 flights and 300,000 passengers. Early morning arrivals from long-haul destinations such as Cape Town, Singapore, and the US were forced to divert back to their origin or airports such as Gatwick, Paris Charles de Gaulle, Shannon, Madrid, Amsterdam, and Manchester. Major airlines such as British Airways, Virgin Atlantic, and American Airlines have all faced severe disruption with cancelled and re-routed flights.

The closure of one of the world’s most important aviation hubs has caused disruptions globally. Airports such as London Gatwick are now facing operational challenges as their aircraft stands have become occupied with diverting aircraft. London Gatwick received two Airbus A380s, one Boeing 787-10 Dreamliner, one Boeing 787-9 Dreamliner, one Boeing 777-200, and one Boeing 777-300ER, adding almost an extra 2,000 passengers to the airport in a short space of time.

Following extensive efforts by engineers and emergency services, power was gradually restored to Heathrow on the evening of March 21. A British Airways A350-1000 was the first aircraft to touch down on runway 09L, coming from Manchester. Critical systems, including air traffic control, baggage handling, and security screening, were brought back online in a phased approach to ensure safety. By the early hours of March 22, Heathrow reopened for limited operations, prioritising stranded passengers and essential flights.

As of midday March 22, flight schedules were still heavily disrupted, with airlines working to reposition aircraft and crew.

Despite the challenges, Heathrow’s rapid response teams and emergency services have been praised for their swift action in mitigating further disruptions. An investigation into the cause of the fire is now underway to prevent future occurrences.

Heathrow is currently the base for 90 different airlines, including the UK’s flag carrier British Airways and Virgin Atlantic. It is also Europe's largest airport, with more than 83.9 million passengers travelling through its terminals in 2024.