Hundreds of anti-lockdown protesters descended on central London on Thursday evening to oppose tough coronavirus rules that came into force in England the previous night.
Very few of the thousands of protesters, who took to the streets near Trafalgar Square and the Strand, wore face coverings or were socially distanced. They shouted slogans including “Freedom” and “No more lockdown”.
Police officers urged demonstrators to go home, saying they were breaking Covid-19 restrictions, and at least four protesters were arrested.
The Metropolitan Police said that protesters were ignoring directions from officers and warned that further action would be taken against those who did not follow the rules.
“This gathering is unlawful and is putting others at risk,” the Met said on Twitter.
“We are directing those there to go home. Failure to do so will result in enforcement action.”
Prime Minister Boris Johnson on Saturday said that a strict new lockdown would begin at midnight on Thursday across the whole of England, to try to curb the surging coronavirus cases.
The new measures, which affect 56 million people, have included the closure of restaurants, cafes, pubs and non-essential shops, and people have been encouraged to work from home.
Thursday's protest was the British capital's fifth anti-lockdown rally since the pandemic began in the spring.
The UK originally went into strict lockdown on March 23 for three months before easing measures and opening up the economy.
Britain has had a surge in coronavirus cases over the past few weeks.
On Thursday, the country reported 24,141 new coronavirus cases and 378 more deaths, taking its total number of Covid-19 fatalities to 48,120.
Earlier on Thursday, Mr Johnson called for a united front to tackle the virus.
"While it pains me to have to ask once again for so many to give up so much, I know that together we can get through this," he said.
"We can do this, we will do this by December 2."
Mr Johnson promised that compliance could lead to "as normal a Christmas as possible".
The Bank of England pledged an extra £150 billion ($195bn) in economic support, on top of new Treasury measures to subsidise the wages of furloughed workers until March 2021.