Police clashed with anti-lockdown protesters at a demonstration in central London as officials tried to end the event.
Thousands of people gathered in Trafalgar Square on Saturday with various signs, flags and placards to attend a rally that we disagree with. No one seemed to be wearing face coverings or keeping social distance.
But the Metropolitan Police said on Twitter that they are telling the crowd to disperse for failing to comply with social distancing rules.
The force said protesters were asked to leave, warning that anyone who stays could be subject to enforcement action.
Officials held the crowd in Trafalgar Square and protesters threw water on them while the crowd sang “Pick your Side” to the officers.
Bottles were thrown and police used batons against protesters, some leaving visible injuries.
At least three protesters and one officer were treated by medical staff.
Police said: “Crowds in Trafalgar Square have failed to meet the terms of their risk assessment and are putting the virus at risk.
“This invalidated their risk assessment and we told the organizers that they are no longer exempt from the regulations.
“We are now asking those in Trafalgar Square to go. The officials will deal with crowds and inform them of this development.
“If you go now you can protect yourself and keep officials from taking enforcement action.”
The police had previously searched a man and confiscated a makeshift shield that he was wearing.
The protest comes a week after a separate incident in which more than a dozen officers were injured when a “small minority” targeted the police and more than 32 people were arrested.
The Met said it worked with organizers throughout the week to remind them of their legal obligations and to explain that the events may violate coronavirus regulations.
While protests in England are exempt from the “rule of six”, organizers must provide a risk assessment and adhere to social distancing.
Police said some organizers did, but where they did not, the Met would “increase engagement and encourage participants to disperse”.
They added that enforcement “remains a last resort but will be carried out when necessary”.