A sonic boom has been heard in Cornwall caused by RAF F-35 Lightning aircraft undergoing training.
In a statement, an RAF spokesperson confirmed the aircraft were "completing operational training inside the supersonic offshore range area".
The F-35 is Britain's newest and most advanced military jet, capable of operating on land and at sea from an aircraft carrier.
The aircraft concerned were approximately 25 miles off the coast when taking part in the supersonic flight training – which is considered normal.
Supersonic flight in offshore military training ranges is routine for RAF and allied fighter aircraft.
Under normal environmental conditions, such events are sufficiently far out to sea to not cause sonic booms heard on the mainland.
However, climatic conditions at the time may have been a factor.
The spokesperson added "any inconvenience caused to local residents is regretted".
A sonic boom is caused when an object travels at more than 767mph – the speed of sound.
Last month, the RAF confirmed a sonic boom above Norwich was created by a Hawk jet on a test flight.
A sonic boom was also heard across London, Cambridgeshire and Essex last month after two RAF Typhoons scrambled to intercept a civilian aircraft.
Cover image: Library image of a British F-35B (Picture: MOD).