Police have let staff back into Terminal Two at Heathrow Airport.
The staff were allowed back into the terminal after a suspect bag was found to be innocent.
A Heathrow spokeswoman said the bag had been checked and cleared.
“Passengers have been allowed back into the terminal. There may be some further disruption but we hope to resume a normal service as soon as possible,” she said.
Travellers remained standing outside and an official told the public that they would be let back into the terminal as soon as possible.
The airport was asking all passengers who were set to fly from Terminal 2 to keep in contact with their airline.
Service delivery terminal manager Rowena Thompson said: “There has been a security alert, an item that police are not happy with. We’ve been asked to evacuate everyone to this point at this time, and that’s what we’re doing.”
Planes were still leaving the other terminals this afternoon.
Andy Beller, 24, who was travelling to France with his girlfriend, said: “We were next in the queue to go on the flight and then we were called out.
“Our flight is in 25 minutes but I’m not very happy because we haven’t been getting any information about what has been going on. We’ve just heard rumours that the terminal could be closed for two hours or indefinitely.”
Authorities later told passengers who had flights before 2pm to re-enter the building.