A British Airways Boeing 747 bound for New York has to return to Heathrow within minutes of take off after a handle on one of the doors was moving.
The aircraft, with 296 passengers and 15 crew, was 11 minutes into the flight when a cockpit light indicated a problem with a cabin door.
The 747 returned to Heathrow on Saturday morning and an investigation has begun.
Passengers were put on another flight to New York.
A BA spokesman said the flight returned to Heathrow “as a precaution because the handle on one of the doors was moving”.
The spokesman added: “At no time was the door open.”