Two RAF jets which flew over Derbyshire this morning causing a 'sonic boom' were responding to a 'security alert' on a plane.
Residents reported hearing a 'loud bang' just before 10am this morning and said homes were 'shaking' and many car alarms were sounding.
It has now been confirmed the sonic boom caused by two RAF jets responding to a security alert on a Air India Boeing 777 that had to be diverted into London Stansted Airport.
An RAF spokesman said: "The RAF can confirm QRA Typhoons were launched this morning from RAF Coningsby to intercept a civilian ac [aircraft].
"The ac was escorted to Stansted. The Typhoons transited at supersonic speed for operational reasons; any inconvenience caused to local residents is regretted."
A spokesperson for Essex Police said: "An aircraft was diverted to Stansted Airport at around 9.50am today following reports of a security alert. The plane is currently at the airport and officers are making enquiries."
And a spokesperson for Stansted Airport said: "An Air India Boeing 777 diverted into London Stanstead Airport at approximately 10.15am and landed safely with Essex Police in attendance.
"It is parked on an isolated stand away from the normal airport operations.
"Our runway has now re-opened and is fully operational. We are very sorry for any delays and disruption caused by the incident, but our first priority is always the safety of passengers and staff."
Earlier Derbyshire police tweeted: "If you heard a loud bang over Derbyshire today, this was as a result of a Royal Air Force jet passing over that caused a sonic boom."
"And Derbyshire Fire and Rescue Service tweeted: "Loud bangs that could be heard across Derby and and parts of Derbyshire are being attributed to a sonic boom caused by a low flying aircraft."