A man has been arrested after a car crashed into the gates outside Downing Street.
The Metropolitan Police said he had been arrested by armed officers on suspicion of criminal damage and dangerous driving.
There were no reports of any injuries and inquiries are ongoing.
Police set up a cordon in Whitehall, the main road running past Downing Street, as officers with sniffer dogs were seen outside the gates.
The incident happened at 16:20 BST, police said. The road has now reopened.
Witnesses saw one man being led away by police.
Footage of the car,identified as a silver Kia, shows it slowing down as it approaches the main entrance to Downing Street, the home of UK Prime Minister Rishi Sunak and his family.
The car appears to slow down as before it hits the gates, which are staffed round the clock by armed and unarmed police officers.
The prime minister and the chancellor were in Downing Street at the time of the crash. Mr Sunak has since left for a scheduled visit.
The car remains outside the gates, surrounded by police tape.
The incident comes as many civil servants in government departments were leaving their offices for the day.
