Scotland Yard said three men, aged 58, 48 and 36, were taken into custody aboard the plane Friday as it sat on a runway waiting to leave for Dubai, saying the men were arrested on suspicion of making a bomb threat, The Daily Telegraph reported.
A witness told Britain's Sky News that five armed policemen rushed aboard the plane and quickly handcuffed one of the men, described as a white male.
Emirates Airlines released a statement saying the men were arrested after "remarks" were made as the plane prepared for takeoff.
"Following remarks made as Emirates flight EK004 prepared to depart London Heathrow for Dubai yesterday evening (Friday), crew alerted the Metropolitan Police who subsequently boarded the aircraft and detained three passengers," the statement said. "All 331 passengers subsequently disembarked as police undertook security precautions."
The Telegraph said there were reports the arrested men had been drinking.