Three men have been arrested on suspicion of making a bomb threat on a plane as it readied for take-off at Heathrow airport.
Armed counter-terrorist officers boarded the Dubai-bound Emirates flight last night after a "verbal threat" was made to air crew at 9.15pm.
The Metropolitan police said the three men, aged 58, 48 and 36, were in custody. It is thought they were all British men travelling in economy class.
One passenger said she saw armed police board the flight and take a man off in handcuffs.
Cameron McLean told Sky News: "Police just swarmed the guy and rushed him out. I think he was a white male. There was another one but I didn't see him."
The man was removed in handcuffs then sniffer dogs were brought on board, McLean said.
Police today released the plane, which had been carrying 331 passengers, to the airline after finding no dangerous items.
Emirates said passengers had been given hotel accommodation overnight and the flight would now leave at 3pm today.
A statement from the airline said: "Following remarks made as Emirates flight EK004 prepared to depart London Heathrow for Dubai [yesterday] evening, crew alerted the Metropolitan police who subsequently boarded the aircraft and detained three passengers.
"The safety and security of all our passengers is paramount. Police are currently assessing the situation and we apologise for the inconvenience to our passengers."
The incident comes amid heightened tension at airports around the world in the wake of the botched bombing of a US-bound airliner on Christmas Day.
A series of extra security measures have since been introduced, including extra baggage checks, body searches and bans on the use of electronic equipment on aircraft.