Dramatic footage shows armed police jumping over barriers to surround a car which crashed into security barriers outside Houses of Parliament and left a number of pedestrians injured.
The area around the Palace of Westminster is on lockdown after police swarmed the scene early on Tuesday morning (August 14), with Scotland Yard now confirming a man has been arrested.
Images posted to social media showed a suspect surrounded by officers, who swooped in on the car at around 7.37am, being led away from the vehicle in handcuffs.
Streets around Parliament Square, Millbank and Victoria Tower Gardens have been cordoned off while police, ambulances and firefighters arrived at the scene, at Parliament Square.
The Metropolitan Police said: "At 7.37am today, a car was in collision with barriers outside the Houses of Parliament.
"The male driver of the car was detained by officers at the scene. A number of pedestrians have been injured. Officers remain at the scene. We will issue further info when we have it."
Later, in a follow up statement, police added: "A number of pedestrians have been injured. We await an update on their condition, however officers do not believe that anyone is in a life-threatening condition."
Footage posted on Twitter after the crash shows armed police jumping over barriers to reach the wrecked car.
Speaking to the Press Association, eyewitness Ewalina Ochab said: "I think it looked intentional - the car drove at speed and towards the barriers.
"I was walking on the other side [of the road]. I heard some noise and someone screamed. I turned around and I saw a silver car driving very fast close to the railings, maybe even on the pavement."
"The person driving did not go out" of the vehicle, she added. Ms Ochab also suggested that the vehicle did not appear to have a front registration plate when it crashed.
Members of the public and press have been moved back further from the area as police put up a "Terrorism Act cordon", according to an officer at the scene.
The cordon has been extended past the Cenotaph on Whitehall - a five-minute walk from the scene at Old Palace Yard.
Westminster station has been closed for both entry and exit due to the security alert, Transport for London said.
Passengers are still able to change between lines at Westminster.