A man has been detained by police after dousing himself in petrol outside the Houses of Parliament.

The man, who was also carrying a lighter, was rugby tackled to the ground by armed police who were patrolling nearby.

Witnesses described seeing the man close to Parliament's Carriage Gates cover himself with a flammable liquid that smelt strongly like petrol.

Huw Merriman, the Conservative MP for Bexhill and Battle, who witnessed the incident, tweeted his praise for the police who he said had responded bravely and quickly.

He wrote: "Man next to me at Parliament’s carriage gates appears to have poured (what smells like) petrol on himself. Incredibly brave response from police, who are now helping him."