The Metropolitan Police Service has tweeted that at around 16:20 local time a car collided with the gates of Downing Street on Whitehall, London.
Armed officers have arrested a man at the scene on suspicion of criminal damage and dangerous driving. There are currently no reports of any injuries. The main Whitehall road outside Downing Street has been closed.
Earlier this week, a man was arrested for driving into security barriers near the White House.