An image has emerged of the moment a man suspected of carrying a knife was arrested by armed police outside Parliament.
Officers placed the entire Parliament complex on lockdown during the incident , with bystanders reporting the man in a grey hooded top being tasered by police.
One photo shared on social media appeared to show the suspect being held at gunpoint and then handcuffed.
Police said a man in his 30s was being held on suspicion of possession of a knife "near to the Palace of Westminster". They said the incident was not believed to be terror-related.
"There are no reports of any injuries," the Metropolitan Police said.
A commotion was heard outside Parliament shortly after 11.10am, and armed police ran towards the gates to New Palace Yard, the scene of the terrorist attack on 22 March in which PC Keith Palmer was stabbed to death.
Joe Murphy, the political editor of the Evening Standard, said there were shouts of "knife knife knife" and a man was brought down by police with a Taser.
The gates to the Palace of Westminster were then shut and journalists inside were told they could leave.
St Stephen's Gate and Carriage Gate were locked, with a number of police vehicles and officers gathered in New Palace Yard.
