A sonic boom has been heard across areas of London, Cambridgeshire and Essex after two RAF Typhoons were scrambled to intercept a civilian aircraft.
The Quick Reaction Alert fighter jets were scrambled from RAF Coningsby in Lincolnshire to intercept the civilian aircraft after it "lost communications", a Royal Air Force spokesman said.
The aircraft was "intercepted and safely escorted to Stansted", the spokesman added.
A sonic boom is created when an object moves through air faster than the speed of sound, 767mph.
The hashtag #sonicboom trended on Twitter on Tuesday after the sound on Tuesday afternoon.
Writing on the social media site, Kendra Little in Cambridge said: "At first I thought something had fallen from the sky and hit the roof. Then I thought a bomb had gone off."
WATCH: The sonic boom was captured on a doorbell camera in east London.
Sharon Pinner tweeted she was running a few miles south of Cambridge when she heard the sonic boom, which she said "sounded like an explosion and the air seemed to shake".
Samantha Hay in Essex wrote the boom sounded similar to "slamming doors".
Sam Harrison, from Hornchurch in east London, captured the sonic boom on his doorbell camera.
He said: "At first I thought it was either an explosion or an earthquake … I ran outside expecting to see a lot of smoke."
The Royal Air Force spokesman said: "Quick Reaction Alert Typhoon aircraft were launched this afternoon from RAF Coningsby to intercept a civilian aircraft that had lost communications; subsequently, communications were re-established, the aircraft was intercepted and safely escorted to Stansted.
"The Typhoon aircraft were authorised to transit at supersonic speed for operational reasons."
There have also been reports of people hearing the sonic boom in West Suffolk.
Cover image: Library photo of an RAF Typhoon (Picture: RAF).