A total of 41 people were arrested and 22 officers were injured as Black Lives Matter protests took place in central London over the weekend, police said.
Thousands of anti-racism protesters descended on the capital on Saturday and Sunday over the death of unarmed black man George Floyd in US police custody.
Mr Floyd, 46, died after a white police officer knelt on his neck for more than eight minutes in Minneapolis. Derek Chauvin, the former officer, has been charged with murder. The protests passed largely peacefully but heated skirmishes erupted in Whitehall on both nights.
Prime Minister Boris Johnson said they were “subverted by thuggery” and that the violence was a “betrayal” of their cause.
In shocking scenes on Sunday night, police officers ran for cover as they were pelted with missiles including glass bottles and fireworks, while one was pictured bleeding on the street.
A dispersal order was enforced in Westminster until 6am on Monday morning as riot police battled into the night to move a group of about 50 violent protesters on.
Meanwhile, a lone activist was pictured scaling The Cenotaph, the national memorial to the fallen in the First World War, and attempting to set the Union Jack flag alight.
The Winston Churchill memorial in Parliament Square was also defaced and daubed with “was a racist” graffiti.
It came after a policewoman needed surgery after reportedly suffering a collapsed lung, broken collarbone and shattered ribs as she fell from her horse, which bolted as flares and missiles were thrown by protesters amid chaos outside Downing Street on Saturday night.
The Met said the majority of the twelve arrests made on Sunday were for public order offences and one was for criminal damage following the incident at the Cenotaph.
On Saturday alone, 29 people were arrested at the protests, while 27 were injured.
Superintendent Jo Edwards, spokesperson for the protests, said: “Regrettably officers were faced with further scenes of violence and disorder following a day of predominantly peaceful protest throughout the capital.
“This is a hugely impassioned movement and we understand the public’s desire to have their voices heard – however it is not right that this passion has turned into violent attacks on officers.”
Thousands gathered outside Downing Street following a huge march and chants of “black lives matter” outside the US Embassy in Vauxhall on Sunday afternoon, defying the ban on mass gatherings during lockdown.
On Saturday, social distancing was seemingly ignored as thousands flooded Parliament Square and marched through central London to Downing Street via Victoria.
Protests were also held in Manchester, Edinburgh, Newcastle, Cardiff, Sheffield and Bristol, where BLM activists tore down a statue of Edward Colston, the 17th century slave trader, and threw it into the city’s harbour.
On Monday morning, the chairman of the Police Federation, which represents all officers in England and Wales, criticised Avon and Somerset Police for its decision not to intervene in a protest in Bristol where a statue of a slave trader was torn down.
John Apter told BBC Breakfast: “To have no police presence there I think sent quite a negative message.
“I understand there has been a lot of controversy about this statue for many years – so the question is why didn’t those in the local authority consider taking it down long before rather than waiting for these actions?”
The force confirmed it had launched a probe to identify "a small group of people who clearly committed an act of criminal damage".
BLM protesters also laid siege to the M6 motorway near Coventry on Sunday evening as they walked down the carriageways with placards.
The protests went ahead as planned despite Health Secretary Matt Hancock and Home Secretary Priti Patel joining police chiefs pleading for people to stay indoors amid the lockdown.
