A man believed to have been carrying a knife has been arrested by armed police outside the gates of parliament.
Officers held the man on the ground at gunpoint at the entrance to New Palace Yard, the scene of a terrorist attack in March in which a police officer, PC Keith Palmer, was killed.
The suspect, wearing a grey hoodie and black trousers, was detained and searched by three officers by the railings in front of Carriage Gate, while four or five other officers patrolled the area nearby.
Witnesses told the Guardian the man had been Tasered. There were reports that officers shouted "knife, knife, knife".
Police say they have not declared it a terrorist incident, but Scotland Yard's counter-terrorism command is investigating. This is because of the location and the terrorist attack on Westminster on 22 March, and current high level of jihadi attack planning. In a statement the Met said: "At this time it is too early to understand the motivation so we have not declared this a terrorist incident.
However given the location, the circumstances and recent tragic events, the MPS counter-terrorism command will be investigating this incident. "We remain open minded as to whether terrorism was a motive." After searching the man, officers carried away a plastic bag containing a belt and mobile phone and the suspect was led to a police van and driven away. Metal barriers were quickly put in place along the front of the Houses of Parliament, blocking public access to the pavement in front of the building.
'The man, aged in his 30s, was arrested on suspicion of possession of a knife. There are no reports of any injuries,' Met police said.