Statues of historical figures including Winston Churchill, which have been at the forefront of demonstrations by anti-racism groups, were boarded up on Friday (June 12) ahead of the expected protests in London.
Mayor Sadiq Khan said the police had intelligence that extreme far right groups were coming to London and he was concerned sites with statues would be a flashpoint for violence.
Khan also said that people should not join demonstrations during the coronavirus pandemic as there was evidence from the United States that those attending them had caught it.
The statue of World War Two leader Churchill outside Parliament was sprayed with graffiti last week after what had been a mostly peaceful demonstration over the death of George Floyd, an African American who died after a Minneapolis police officer knelt on his neck for nearly nine minutes.
British Prime Minister Boris Johnson said on Friday it was "absurd and shameful" that the statue of Churchill was at risk.