"Initially, the pilot told us there were technical problems, and we waited for about an hour, and at one point we noticed that police vehicles were encircling us, with dozens of armed officers and firemen", according to James Anderson, a passenger of the British Airways flight evacuated, quoted by Franceinfo.
British Airways said in a statement: "The safety and security of our customers and crew is always our top priority".
Passenger, James Anderson, 20, said those on board were informed by the pilot that an individual had made a direct threat against the aircraft.More news: California lawmakers approve presidential primary in March
Airport officials told the media that the threat was made about 10 minutes before the London bound British Airport flight BA303 was due to take off.
He said passengers have remained calm despite the situation. We will all be led off the aircraft and baggage searched in due course. "We would never operate a flight unless it is safe to do so".
Mr Anderson claimed 'Everybody's been individually searched by armed officers and given all clear.
An airport spokesman confirmed the evacuation, saying it was for a "security reason". Now hold luggage being searched by dogs'.
The security scare came as a second man was arrested in London in connection with Friday's partially exploded bomb at Parsons Green Tube station.