More than 30 people have been arrested as thousands of anti-lockdown protesters descended on central London.
Officers in riot gear were confronted by large groups calling for restrictions to be lifted in ugly scenes in the capital.
Bottles were hurled as tempers frayed in Hyde Park before demonstrators marched towards Westminster.
The Met Police said 33 people had been arrested by 645pm, mostly for breaching Covid regulations.
Protesters gathered in Hyde Park to voice their anger over lockdown measures, as well as the government’s Police, Crime, Sentencing and Courts Bill.
Actor Laurence Fox, who has previously signaled his intention to stand for London mayor, was among them – prompting sharp criticism from followers on social media.
Pictures show thousands of people without face masks blocking traffic on London’s Park Lane.
They also marched through Hyde Park and were pictured and filmed clashing with police in Piccadilly.
The Met Police posted on Twitter: “As of 18:45hrs, 33 people have been arrested by officers policing the gatherings in central London.
“Most of the arrests have been for breaching COVID regulations.”
It comes as protests are held in other cities across the UK, with hundreds of demonstrators marching through central Manchester today.
Piers Corbyn, the brother of former Labour leader Jeremy Corbyn, gave a speech at Hyde Park corner.
Protesters were seen walking through Hyde Park chanting “stand up, take your freedom back!” and “Burn your mask!”
A man held a banner reading: “Free your face.”
Police urged people to stay home and adhere to coronavirus lockdown restrictions.
