A loud sonic boom caused by RAF planes has woken people across north London and shaken houses.
People tweeted that a loud “explosion” had woken them up at around 04:20 GMT – with houses shaking and reports of police sirens straight after.
It is believed that loud noise was two RAF Typhoons launched from RAF Coningsby in Lincolnshire to an unresponsive aircraft.
It was reported by people across north London, Hertfordshire and Bedfordshire.
The Met Police subsequently confirmed the bang was the result of RAF aircraft.
Mil Radar which monitors Royal Air Force activity tweeted:
Kiran Topan tweeted this video:
Actor Logan Dean tweeted that he was among those who heard the noise:
What causes a sonic boom?
When an aircraft approaches the speed of sound (768mph or 1,236km/h), the air in front of the nose of the plane builds up a pressure front because it has “nowhere to escape”, said Dr Jim Wild of Lancaster University.
A sonic boom happens when that air “escapes”, creating a ripple effect which can be heard on the ground as a loud thunderclap.
It can be heard over such a large area because it moves with the plane, rather like the wake on the bow of a ship spreading out behind the vessel.