Tens of thousands took to the streets of London today, rallying for a second day to condemn police brutality after the killing of George Floyd in Minneapolis, with some wearing face masks bearing the slogan "Racism is a virus".

Some Black Lives Matter demonstrators clashed with police at the junction of Parliament Street and Whitehall with scuffles between the crowd and baton-wielding officers.

London police chief Cressida Dick said 27 officers had been injured in "shocking and completely unacceptable" assaults during anti-racism protests in central London this week, including 14 yesterday. Two were seriously hurt and an officer who fell from her horse underwent surgery.

Authorities urged protesters not to gather in London again today, warning they risked spreading Covid-19.

But demonstrators still packed the road outside the US Embassy on the south bank of the River Thames. Journalists on the scene estimated the crowd to be in the tens of thousands.

Protesters later marched across the river towards Westminster and Downing Street. In Parliament Square, many attached their placards to the railings outside the UK parliament.

Protesters and police confront each other in central London at Black Lives Matter rally

Rapper Stormzy joined anti-racism demonstrators at Parliament Square. He did not speak but listened quietly as the crowd, many of whom were black, spoke about the struggle for equality and the need for solidarity.

Earlier, protesters in Bristol have pulled down a controversial statue of a 17th century slave trader. The bronze memorial to Edward Colston, situated in Bristol city centre since 1895, was torn down after crowds left College Green.

It had been the subject of an 11,000-strong petition to have it removed.

Images showed crowds rushing to stamp on the statue, which stood in Colston Avenue. Protesters knelt on the statue, in reference to George Floyd, who died under the knee of a police officer in Minneapolis.

The statue was then rolled along the road and pushed into the harbour.

Protester John McAllister, 71, tore down black bin bags used to hide the statue to denounce it in front of fellow protesters.

He told PA: "It says 'erected by the citizens of Bristol, as a memorial to one of the most virtuous and wise sons of this city'.

"The man was a slave trader. He was generous to Bristol but it was off the back of slavery and it's absolutely despicable. It's an insult to the people of Bristol."

The statue of Edward Colston being toppled into the waterfront at Bristol

According to Historic England, the statue was sculpted by John Cassidy, of Manchester, with an inscription that read "erected by citizens of Bristol as a memorial of one of the most virtuous and wise sons of their city AD 1895".

Colston's involvement in the slave trade through the British-based Royal African Company was the source of much of the money which he bestowed in Bristol, the website added.

Avon and Somerset Police superintendent Andy Bennett said 10,000 people had attended the Black Lives Matter demonstration in Bristol and the majority did so "peacefully".

But he added officers would be seeking to identify protesters who pulled down a statue of slave trader Edward Colston.

Boris Johnson said the anti-racism demonstrations had been "subverted by thuggery".

"People have a right to protest peacefully & while observing social distancing but they have no right to attack the police," the Prime Minister tweeted.

"These demonstrations have been subverted by thuggery - and they are a betrayal of the cause they purport to serve.

"Those responsible will be held to account," he said.