Thirty-three people have been arrested during a protest by anti-lockdown campaigners in central London, Sky News reports.
Most of the arrests were for breaching COVID-19 regulations, Scotland Yard said.
Officers were forced to run back to their vans as protesters threw bottles and cans at them in Hyde Park.
A group of about a hundred chased police vehicles as they left the area, punching and kicking them.
Members of the public with small children were seen leaving the area.
Around a hundred officers in riot helmets and carrying shields arrived in the park and urged people to go home.
The Met tweeted earlier: "Officers will take enforcement action where necessary. This could be a fixed penalty notice, or arrest."
