Two fighter jets were deployed from RAF Coningsby on Wednesday, October 29 to intercept a Latvian cargo aircraft near London.
The Typoons from the Lincolnshire base were deployed as part of the Quick Reaction Alert system, and were requested to escort the foreign aircraft after it lost contact with nearby air control.
The Latvian private aircraft, confirmed to be a Ukrainian made Antonov An-26, was flying in skies south of London when it began to cause concern for authorities just after 4pm.
It is reported to have taken an unexpected detour around London on its way to Birmingham.
In Kent and nearby counties at around 4.40pm, reports of a sonic boom from the Typhoons have been widely reported upon meeting the aircraft.
The jet planes escorted the plane to London Stansted Airport, where police met with the aircraft at around 5.20pm.
An 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 fulfill 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 are not treating the incident as suspicious and it will continue its flight later this evening.