A man has been detained by armed police outside the Palace of Westminster.
A bearded man, wearing black trousers and a grey sweatshirt, was seen being held against the fence with his arms behind his back by a police officer.
The incident is not thought to be terror related. The Carriage Gates entrance to Parliament is closed.
Scotland Yard said the man - aged in his 30s - was arrested on suspicion of possessing a knife.
He was held with his arms against his back just yards from the forecourt of the building, where PC Keith Palmer was stabbed to death by terrorist Khalid Masood in March.
BBC deputy political editor John Pienaar said the latest incident ended very swiftly with the man being taken away in a police van.
More:
http://www.bbc.co.uk/news/uk-40303300
