What we know so far

--Car collides with pedestrians, parliament security barriers

--Man in his twenties arrested on suspicion of terrorism

--Injuries not believed to be serious

--Second apparent attack on parliament in 18 months

--Britain on second-highest threat level

Two people treated following rush-hour car crash

A man in his twenties has been arrested in London on suspicion of terrorism offences after a car crashed outside the Houses of Parliament in Westminster on Tuesday morning, in what police are describing as a terrorist incident.

At 7:37 am, a vehicle ploughed into a number of cyclists and pedestrians before crashing into barriers outside Parliament.

Police were seen surrounding the car and armed officers arrested a man at the scene. They have reported that no-one else was in the car and "no weapons have been recovered at this stage". The Metropolitan Police’s Counter Terrorism Command is investigating the incident.

Westminster underground station remains closed and streets around Parliament, including Millbank and Parliament Square have been cordoned off, and the London Ambulance Service said it had taken two people to hospital with non-life-threatening injuries.