Video report by ITV News UK Editor Paul Brand
Violence at the "Kill the Bill" protest in Bristol has left 20 police officers injured with two needing hospital attention, sparking condemnation from across the country.
Avon and Somerset police chief constable Andy Marsh promised "very serious consequences" for all those involved.
Thousands had gathered to protest against the government’s Police, Crime, Sentencing and Courts Bill, but the demonstration soon turned violent after being "hijacked by extremists", Chief Constable Marsh said.
“Officers were pelted with stones and missiles and fireworks and it was a terrifying situation for them to deal with," he added.
“We have 20 officers injured, two of them seriously."
The two police officers who were seriously injured and were taken to hospital suffered from broken ribs, a broken arm and a punctured lung.
Chief Constable Marsh said the numbers at the demonstration “very quickly” rose to possibly as many as 3,000 people and a group of 400 or 500 “who really were intent on violence, damage and criminality started to commit crimes, damage police vehicles” at about 6pm outside Bridewell police station in central Bristol.
Avon and Somerset Police said seven people have been arrested – six for violent disorder and one for possession of an offensive weapon.
Prime minister Boris Johnson said that while people "obviously" had the right to protest the scenes in Bristol were "unacceptable".
Earlier, Home Secretary Priti Patel branded the scenes “unacceptable” and said “thuggery and disorder” would never be tolerated.
Bristol mayor Marvin Rees, who said he had “major concerns” about the Police, Crime, Sentencing and Courts Bill, condemned the thuggery and said the disorder would be used to justify the legislation.
"We're disgusted, absolutely condemn what's gone on, and what they've done is they haven't just smashed windows, we have injured police officers, broken ribs, broken arms, of a police service, that has served us incredibly well over the last year," Mr Rees told ITV News.
"These people who have done this have taken from us this year in which we've navigated very tense situations and kept peace."
He added: "I draw a hard line between those people out smashing up my city yesterday and the Bill. They have got nothing to do with the Bill.
"I would imagine, and I think experience would suggest, that there are a group of people running around the country looking for any opportunity to enter into physical conflict with the police or representatives of what they see is the Establishment."Mass gatherings are currently banned under coronavirus legislation and anyone breaching the regulations could be fined.
Many who attended the protest on College Green were wearing face masks and carried placards, saying: “Say no to UK police state” and “Freedom to protest is fundamental to democracy” and “Kill the Bill”.
What started as a non-violent demonstration on Sunday afternoon turned violent after hundreds of protesters descended on the New Bridewell police station.
Later, protesters attempted to smash the windows of the glass-fronted police station.
They also tried to set fire to one of the marked police vans parked outside the station but the small flames were quickly extinguished by riot officers.
Other protesters set fire to a police van parked on Bridewell Street, near to the police station.
Rioters smashed the windows of the police station and also destroyed Avon and Somerset Police vehicles parked nearby, setting fire to a car and a van.
Cars parked in a multi-storey car park adjacent to the police station were also damaged by protesters.
Avon and Somerset Police said its officers had missiles and fireworks thrown at them and used mounted officers and dogs to disperse the mob.
A clean-up operation is now underway in Bristol after the violent scenes left the city in a state of chaos.
Workers were cleaning up the mess left from the protest on Monday morning
The mindless violence was condemned by the Home Secretary who said "thuggery and disorder by a minority will never be tolerated", police federation representatives and local leaders.
Andy Roebuck, chairman of the Avon and Somerset Police Federation, said: “Disgusting scenes in Bristol by a mob of animals who are injuring police officers, members of the public and damaging property.
“We have officers with suspected broken arms and ribs.
“This is so wrong.”
Social Care Minister Helen Whately told ITV News the violence was "completely unacceptable," as was wishing the injured police officers a full recovery.
Police and crime commissioner Sue Mountstevens said: “I cannot condemn enough the scenes of violence and destruction that we witnessed yesterday and I know these feelings are felt by the majority of the city and beyond."
She said the cost to repair the damage done to the city would be "substantial."
Chief Superintendent Will White, of Avon and Somerset Police, said: “These scenes are absolutely disgraceful and they will be widely condemned by people across the city.
“There can never be any excuse for wanton disorder.
“All those involved in his criminal behaviour will be identified and brought to justice.
“There will be significant consequences for behaviour such as this.”
The Police, Crime, Sentencing and Courts Bill would give the police in England and Wales more power to impose conditions on non-violent protests, including those deemed too noisy or a nuisance.
Those convicted under the proposed legislation could face a fine or jail.