A man has been arrested on suspicion of making a hoax bomb threat after a Qatar Airways plane was escorted by an RAF jet into Manchester Airport because of a "possible device" on board.
A spokesman for Greater Manchester Police said the aircraft was accompanied by a fighter jet as it landed "as a result of information received by the pilot about a possible device".
The threat was allegedly made in a letter handed to a member of the crew and passed on to the pilot, who alerted air traffic control before the RAF jet was scrambled.
The aircraft was the Qatar Airways flight QR23 from Doha to Manchester and the RAF plane was a Typhoon from RAF Coningsby in Lincolnshire.
The Airbus A330-300, which had 269 passengers and 13 crew on board, landed around 1.30pm in a remote part of the airport.
Passengers said on Twitter that armed police were outside the plane shortly afterwards and images later showed a man in a green T-shirt being escorted off the plane by armed guards.
People disembarked from the plane after the man was detained and it is understood that no bomb or suspicious device was found on board.
Flights in and out of Manchester Airport were disrupted by the incident as the runway was shut for 25 minutes but police said it was "business as usual" by 2pm.
Nine incoming flights had to be diverted to other airports, with five landing at Leeds Bradford airport.
“There are a few minor delays to outgoing flights but we're pretty much back to normal,” an airport spokesman said on Tuesday afternoon.
Footage from on board the plane and on the ground showed the Typhoon flying level with the passenger jet on its left side as it descended.
Chief Superintendent John O'Hare said the safety of those on board as well as those in and around the airport was his "paramount concern" in the police operation.
The flight was number QR023 from Doha and circled twice around the south of the Peak District before approaching the airport, flight data showed.
A passenger, Josh Hartley, tweeted pictures and a video of the RAF plane flying alongside the aircraft, writing: "Okay no [sic] I am worried."
Shortly before 1.30pm, he wrote: "Landed dunno what the f*** is happening."
He appeared to only learn about the possible device on the plane from tweets sent by media outlets.
"We were not told anything," he told the BBC as he waited on the plane.
"We got nothing from [the cabin crew] whatsoever. We had no contact and no information apart from what we saw on Twitter."
Asked how passengers had reacted to seeing the fighter jet alongside the plane he said: "It think it was pretty calm all the way through but I think some people were shaken up."
Paul Bell, who was on his way to the airport in a taxi, told Sky News that he saw the RAF Typhoon meet the passenger plane.
He said: "We heard the fighter jet circling over Stockport, and literally 10 minutes later we saw the plane coming in being followed by it.
"We saw the [RAF Typhoon] coming in, literally flying around the aeroplane.
"It then pinged up on the sat nav that the airport is on lock-down."
Manchester Police said it was "business as usual" for other flights at the airport by 2pm due to a swift response.
Authorities had followed "standard procedure" in dealing with a possible threat, according David Kaminski-Morrow, the air transport editor of Flightglobal magazine.
He said: "In situations like these, the plan is always to get the aircraft down at the nearest available landing site.
"It could be that a threat could have been phoned in and passed on to the captain. It could be that someone on board has spotted something.
"In any event, no one wants to take any chances."
An RAF spokesman said the incident was handled by civilian authorities after the safe landing of the plane.
He added: "We can confirm that Typhoon aircraft were launched from RAF Coningsby in their quick reaction alert role this afternoon to investigate a civilian aircraft whose pilot had requested assistance."
Qatar Airways issued a statement confirming that flight QR23 from Doha to Manchester landed after its scheduled arrival time of 1.15pm.
It continued: "There were 269 passengers and 13 Qatar Airways crew on board. The crew onboard had received a threat about a possible device on board and Qatar Airways immediately took all the necessary precautions to alert British authorities.
"The crew is now fully assisting police at the airport with their inquiries. The safety and well-being of our passengers and crew is our top priority. As this is a matter of a police investigation, we cannot comment further at this time. "