Two men claiming they had a bomb attempted to burst into the cockpit of a flight bound for the UK, triggering fighter jets to be scrambled to intercept the aircraft.
Yesterday's Pakistan International Airlines flight from Lahore to Manchester Airport with 347 passengers on board was diverted to Stansted with an escort from Typhoon jets from RAF Coningsby, Lincolnshire, after the pilot raised the alarm.
According to senior defence sources, the men, British nationals aged 30 and 41, claimed they had a bomb. They were arrested on suspicion of endangering an aircraft by armed police who boarded the plane.
"The cabin crew informed us that they tried to come into the cockpit a few times," said Umari Nauman, a passenger on the flight.
"Because they had been asked not to do that, they got into a bit of an argument with the crew and made a few threats," she told 'Sky News'.
Another passenger on the flight, Mr Munsif, added: "Three to four people boarded and two men were removed from the plane. They were arrested and taken away in handcuffs."
Mashhood Tajwar, the airline's spokesman, said information had been received by Manchester air traffic control saying there was "some security threat".
"But so far it has not been ascertained what was the real motive behind that call," he added.
At Stansted, passengers disembarked safely after the aircraft was taken to a remote area of the airport.
Superintendent Darrin Tomkins, of Essex Police, said the aircraft had been subjected to a forensic examination and nothing had been found.
"This incident is being treated as a criminal offence and remains under the direction of Essex Police," he added.
This was the second time in less than two years that flight PK 709 has been diverted following a bomb alert. In September 2011, the aircraft was diverted to Ataturk Airport, Istanbul, after an emailed threat. (© Daily Telegraph, London)