A terror suspect arrested after a car crashed into a barrier at the Houses of Parliament at high speed is not believed to be known to the security services, police have said.

At least three people were injured when the silver Ford Fiesta hit a group of cyclists and pedestrians waiting for traffic lights to change. Rooftop camera footage shows the car mounting a pavement on the wrong side of the road before, witnesses said, it travelled at up to 50mph for around 40 metres (130ft) and hit a bollard.

Scotland Yard said a man in his late 20s was arrested after the incident at around 7.30am on Tuesday. The suspect was taken to a south London police station, where he remains on suspicion of terrorism offences. He is not co-operating with officers.

Meanwhile, as Theresa May warned of the "severe" threat facing Britain, new figures showed a sharp rise in terrorism investigations, with the number of live cases of suspected plots rising from more than 500 in March to 676 by the end of June.

The Met's counter-terrorism command is leading the investigation into the latest attack. Officers are seeking to formally identify the suspect, but "don't believe this person is known to either MI5 or counter-terrorism police".

The suspect is reported to be from the Midlands and it is believed that he might have travelled to London from Birmingham.