A Dubai-bound Emirates flight with more than 300 passengers on board was grounded minutes before it was due to take off from Heathrow airport on Friday night after three men sparked a terror alert when they reportedly made a “verbal threat”, though it was not known what exactly they said.

Armed officers stormed the plane and the men — all white and aged 58, 48 and 36 — were arrested on suspicion of making a bomb threat. The plane was then moved to a safe area and evacuated.

Passengers, who had to wait for nearly four hours on the stranded plane, were put up in a hotel for the night as the flight was rescheduled for Saturday.

Police with sniffer dogs searched the plane but found nothing suspicious.

There were suggestions that the trio, who had been drinking before boarding the plane, may have made the threat in jest but security officials denied they had over-reacted saying they were not prepared to take any chances.

“We have zero tolerance for those kinds of comments,” one official was reported as saying.

The incident occurred as the plane was taxiing along the runway before the take-off. One passenger, sitting a few rows from one of the alleged suspects, 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 incident came amid heightened security at British airports following the Christmas Day bomb plot in which a Nigerian youth Umar Farouk Abdulmutalab, a former student at a London university, allegedly attempted to blow up a plane over Detroit in America.

New measures, including full body-scans, are to be introduced at Heathrow and other major airports by the end of this month as part of an overhaul of airport security.