Two RAF Typhoons escort a Latvian-registered private plane into Stansted Airport, as a sonic boom from their intervention is heard across South East England
Two RAF fighters triggered a sonic boom across a large area of South East England when they intercepted a foreign aircraft which was "causing concern".
The Typhoons were scrambled to escort a Russian-made Antonov An-26 cargo airliner from Latvia into Stansted Airport.
One Twitter user who monitors aircraft radio traffic claimed on Twitter: "I have just heard a warning go out 'if you do not respond to my orders immediately you will be shot down.'"
Police later said that the incident occurred as a result of a "loss of communication with the aircraft". Having spoken to the three passengers on board they agreed that the plane could continue its journey to Birmingham.
Residents across a large radius of South East England were alerted to the incident when they heard an explosion-like sound at around 16.40 on Wednesday. The noise was reported in Kent, West Sussex, Hertfordshire and Essex.
A RAF spokesman said: "Typhoon aircraft were launched this afternoon from RAF Coningsby to intercept a civilian aircraft south of London which was causing concern to air traffic control authorities.
"The aircraft was safely escorted to London Stansted.
"To fulfil their quick reaction role the Typhoons were cleared to travel at supersonic speed, any noise disturbance as a result of this is regretted.
"Essex Police now have the lead."
An Essex Police spokesman said the plane had been intercepted following a loss of communication but on landing it was established that everything was in order.
He said the military jets were deployed as a precautionary measure when the cargo plane was diverted to Stansted Airport.
He said: "This was due to a loss of communication with the aircraft.
"The aircraft landed safely at Stansted Airport at around 5.20pm.
"All three people who were on board have been spoken to by police. It was established that everything was in order and the reason for the short loss of communication was due to a change in airspace jurisdiction.
"Essex Police is not investigating the incident and the aircraft will be able to continue its journey to Birmingham when it's ready."
Twitter users said the noise caused their windows to shake.
Paul Dunlop tweeted: "Massive explosion-like noise heard down here in Sevenoaks. Whole house shook. Can see people saying they heard it across Kent."
Cleyton Tierney wrote: "Huge bang shook the house, no idea what that was.
"Anyone else hear/feel it?"
Ben Basten added: "Who else felt the earth move and huge explosion in Kent 5 minutes ago? Is the world coming to an end? My house rocked."
A sonic boom is the sound associated with the shockwaves created when an object, such as an aircraft, breaks the sound barrier.
In April, 2012, a sonic boom was heard across five counties from Somerset to Oxfordshire after two fighter jets were scrambled to help a helicopter, after its pilot accidentally emitted an emergency signal.