Police have clashed with demonstrators at a protest in central London against coronavirus restrictions.
Officers used batons to control the crowd, after bottles and water were thrown by demonstrators massed in Trafalgar Square.
At least three protesters and nine officers were injured, while 16 people were arrested.
The Met Police said the protest had been shut down because the crowd was not complying with social distancing.
Earlier on Saturday, thousands gathered in central London to protest against the latest government rules, with very few wearing masks.
Protests are exempt from the rule-of-six restrictions, but demonstrators must social distance; organisers must also submit a risk assessment.
Rules in England limit indoor and outdoor gatherings to six people, with some exceptions.
Officers removed sound equipment and penned the crowd in Trafalgar Square as water and bottles were thrown at them by demonstrators - with some chanting "pick your side".
Two police officers required hospital treatment.
Police used batons against protesters, leaving some with visible injuries.
Reacting, London Mayor Sadiq Khan said: "The reckless and violent behaviour of some protesters has left hard-working police officers injured and put the safety of our city, which is at a critical moment in the fight against this virus, at risk. This is totally unacceptable.
"We cannot let the sacrifices Londoners have made be undermined by the selfish behaviour of a small number.
"Violence of this kind towards officers will not be tolerated and perpetrators will feel the full force of the law."
The Met said the vast majority of crowds had now dispersed.
In a statement on Saturday afternoon, the Met said: "Crowds in Trafalgar Square have not complied with the conditions of their risk assessment and are putting people in danger of transmitting the virus.
"This has voided their risk assessment and we have informed the event organisers they are no longer exempt from the regulations."
Police also confiscated a makeshift riot shield from one man.
The "we do not consent" rally came a week after a separate event which saw more than a dozen officers injured when a "small minority" targeted police and more than 32 arrests were made.
Commenting on events on Saturday, Commander Ade Adelekan - who was leading the Met operation - said: "As the crowds began to swell in Trafalgar Square, it became impossible for people maintain social distancing and keep each other safe.
"In the interest of public safety, officers then worked quickly to disperse crowds. I am grateful to those members of the demonstration who listened to officers and went home.
"However, I am very frustrated to see that nine officers were injured during clashes with a small minority of protestors. This is especially saddening in light of the injuries sustained by officers last weekend.
"We will be supporting those officers who were injured and I wish them a very speedy recovery."