The anti-racism 'Black Lives Matter' protests in the UK have been "subverted by thuggery", Prime Minister Boris Johnson warned on Sunday and added that those responsible would be held to account.

Thousands of people took to the streets of London, for a second day running, to join the chorus to condemn police brutality after the recent killing of George Floyd in Minneapolis.

As numbers diminished, some protesters clashed with the cops.

This comes right after 14 police officers were injured on Saturday with two being in serious condition when the wall of protesters got into a tussle with mounted police officers near Johnson’s Downing Street residence.

"People have a right to protest peacefully and while observing social distancing but they have no right to attack the police," Johnson took to Twitter and said.

"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 added.

People have a right to protest peacefully & while observing social distancing but they have no right to attack the police. 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.

— Boris Johnson #StayAlert (@BorisJohnson) June 7, 2020

Soon after Floyd's death in police custody on May 25, the twin cities of Minneapolis and St. Paul erupted in massive protests which later on spread all across US. 

The official post mortem report of Floyd revealed that the cause of death was due to 'neck compression'.

George died of "cardiopulmonary arrest complicating law enforcement subdual, restraint, and neck compression," and the way of his death was "homicide," the Hennepin County Medical Examiner in Minneapolis announced in a statement.

Other crucial health conditions of Floyd were also listed as "arteriosclerotic and hypertensive heart disease; fentanyl intoxication; recent methamphetamine use."