A man has been arrested by armed officers on suspicion of threatening behaviour at Heathrow Airport.
The Metropolitan Police said they were called at 07:00 GMT to reports of a man seen with a knife at Terminal 3.
However, a man in his 20s was found with a metal object rather than a knife. There were no injuries.
A man was arrested on suspicion of threatening behaviour and is currently in custody at a west London police station.