Extinction Rebellion, which has planned 10 days of action, and other groups gathered at city landmarks on Thursday.

Of those arrested, Scotland Yard said, more than 200 were linked to a demonstration on Lambeth Bridge near the Houses of Parliament.

Extinction Rebellion said police had refused to let peaceful protesters leave the bridge.

The bridge was blocked when some protesters "locked on" and attached themselves to it, police said.

It has since reopened to traffic.

Elsewhere, protesters from the group Animal Rebellion glued themselves to the top and the inside of slaughterhouse truck painted pink.

The vehicle was cordoned off after being parked sideways across Victoria Street.

Protesters also glued themselves to the ground around Parliament, while others staged sit-ins around the perimeter of the parliamentary estate.

Extinction Rebellion said it wants the government to declare a climate and ecological emergency, reduce greenhouse gas emissions to net zero by 2025 and establish a "citizens' assembly on climate and ecological justice".

More protests are planned on Friday and the Met has imposed restrictions on one event due to be held in Parliament Square.

It has ordered campaigners to stay off main roads and to leave the area by 19:00 BST.