A number of planes at Heathrow Airport have been disrupted after its control tower was forced to evacuate.
The alarm on the airfield meant several flights were unable to land or take-off from the airport.
Flights were forced to divert to Gatwick and Stansted airports, while some had to return to their original destinations after take-off.
Heathrow Airport said the alarm has been investigated, and “operations” have started to resume.
No landings or taking offs at @HeathrowAirport . Wonder whats going on? Hearing that there's a fire alarm gone off at the Control Tower? Maybe someone can correct me? @flightradar24 @airlivenet pic.twitter.com/Hm0XojxFp8
— Ket ૐ (@OnTheRoadToYou) July 18, 2018