24 May 2013 Last updated at 09:46 ET
RAF Typhoon jets have been launched to investigate an incident involving a civilian aircraft within UK airspace, the Ministry of Defence has said.
A Pakistan International Airlines plane has been diverted from Manchester to Stansted Airport, a Manchester Airport spokesman said.
An Essex Police spokeswoman added: "An incident has occurred on an aircraft. Police and partners are responding."
The BBC understands that the plane has now landed in Stansted.
BBC defence correspondent Jonathan Beale said that police were expected to meet the plane at the airport.
The plane, flight number PK709, reportedly left Lahore at 09:35 local time. It was due in at Manchester at 14:00 BST.
The MoD said responsibility for the incident had now passed to Essex Police and the Home Office. The MoD was not able to say how serious a threat there was on board.
Philip Baum, of Aviation Security International, told the BBC: "This is certainly a significant incident, however the fact that fighter jets were scrambled to intercept is not unusual.
"We don't know what the incident was: fighter jets are scrambled when there is a bomb threat, when there is a hijack, when the wrong transponder code is used or if an aircraft cannot communicate with the ground. Often the result is when there is an unruly passenger on board.
"What is interesting in this case is that it would appear that the aircraft was only 10 minutes from landing - these are initial reports coming in - when they decided to divert to Stansted. So to actually change a destination 10 minutes from landing would certainly imply that there was some serious incident taking place."
Send your pictures and videos to [email protected] or text them to 61124 (UK) or +44 7624 800 100 (International). If you have a large file you can upload here.
Read the terms and conditions
RAF Typhoon jets have been launched to investigate an incident involving a civilian aircraft within UK airspace, the Ministry of Defence has said.
A Pakistan International Airlines plane has been diverted from Manchester to Stansted Airport, a Manchester Airport spokesman said.
An Essex Police spokeswoman added: "An incident has occurred on an aircraft. Police and partners are responding."
The BBC understands that the plane has now landed in Stansted.
BBC defence correspondent Jonathan Beale said that police were expected to meet the plane at the airport.
The plane, flight number PK709, reportedly left Lahore at 09:35 local time. It was due in at Manchester at 14:00 BST.
The MoD said responsibility for the incident had now passed to Essex Police and the Home Office. The MoD was not able to say how serious a threat there was on board.
Philip Baum, of Aviation Security International, told the BBC: "This is certainly a significant incident, however the fact that fighter jets were scrambled to intercept is not unusual.
"We don't know what the incident was: fighter jets are scrambled when there is a bomb threat, when there is a hijack, when the wrong transponder code is used or if an aircraft cannot communicate with the ground. Often the result is when there is an unruly passenger on board.
"What is interesting in this case is that it would appear that the aircraft was only 10 minutes from landing - these are initial reports coming in - when they decided to divert to Stansted. So to actually change a destination 10 minutes from landing would certainly imply that there was some serious incident taking place."
Send your pictures and videos to [email protected] or text them to 61124 (UK) or +44 7624 800 100 (International). If you have a large file you can upload here.
Read the terms and conditions