A flight of Eurofighter Typhoon jets scrambled from a Lincolnshire operational airbase caused a sonic boom over Peterborough this afternoon.
It happened at about 2pm, when pilots at RAF Coningsby were ordered airborne in response to a 'failure in commmunication' between a commercial aircraft and air traffic control.
The jets were authorised to go supersonic - breaking the sound barrier - causing a sonic boom above the Cambridgeshire city.
An RAF spokesman said: "The Ministry of Defence can confirm that Typhoon aircraft from RAF Coningsby were launched from quick reaction alert this afternoon to investigate a civilian aircraft which had lost radio contact with air traffic control.
"The civilian aircraft re-established communications prior to intercept and was released to proceed en route.
"The Typhoon aircraft were authorised to go supersonic over land for operational reasons.
"Any inconvenience caused to local residents is regretted."
The spokesman added that the operation was a routine part of the RAF's air defence role to protect UK airspace.
Multi-role Typhoon fighter squadrons are based at RAF Coningsby, Leuchars in Fife, in Lithuania on NATO deployment and on the Falkland Islands.
Today and every day, just as during the Battle of Britain, they maintain the highest level of readiness.
Under the direction of controllers at RAF Scampton near Lincoln and RAF Boulmer in Northumberland, the fighhters can be scrambled to intercept, identify and, if required, intervene aircraft approaching UK shores.
RAF aircraft and crews are held on 24-hour 'high readiness' so they can take off within minutes to protect UK sovereign airspace.
The RAF holds a continuous ground readiness posture at RAF Coningsby and RAF Leuchars.