Fifteen police officers were left injured, with two needing hospital treatment, after a south London street party descended into panic and violence.
Footage of the chaotic scene shows men jumping on a police car and smashing in the windows as officers flee.
The trouble flared at what police are describing as an “unlicensed” music event which started in the afternoon and ran into the early hours of the morning.
Four people have been arrested for assault and public order offences. They remain in police custody.
Shocking images circulating on social media show officers being chased by men brandishing improvised weapons.
In one video, a man can be heard telling a group of officers to “back up” as he confronts them with what appears to be a sword.
Another clip shows a man chasing away police shouting “don’t come round here bro … this is what we do” and verbally abusing them.
In another, a woman can be heard saying “yeah” and “nice” as a topless man and angry mob stomp over the police car.
One woman expressed her shock that the car had been wrecked and officers had fled the scene.
Looking at the gutted vehicle she said: “They’ve finished the car. My Lord the police have abandoned their own car.”
Another dumbfounded onlooker said repeatedly: “The police are getting run out of here.”
Scotland Yard said a small number of police vehicles were damaged during the incident.
Officers with riot gear were dispatched to the scene but they were forced to back off as missiles were hurled and they wee goaded by the crowd.
Police said the 15 wounded officers did not suffer serious injuries, although two required hospital treatment.
They said that contrary to reports circulating on social media there had been no reports of stabbings.
The force issued a full statement in the aftermath of the incident saying: “Police were called to Cecilia Road, Lambeth on the evening of Wednesday, 24 June to multiple reports of a large unlicensed music event in the street.
“Officers attended to encourage the crowd to leave the location but they did not engage with police.
“The event continued and more officers attended the scene and the group became hostile towards officers.”
They added: “The event was cleared in the early hours of Thursday, 25 June.
“A section 60 was later implemented in the vicinity of the event to prevent violence.”
She tweeted: “Just last weekend, the whole country came together to praise our heroic police officers for putting their own lives on the line to keep us safe.
“I’ll be picking up with the Met Commissioner immediately.”
Meanwhile, police commander Colin Wingrove responded to the chaos, saying: “Our role is to protect the public and ensure guidelines are adhered to in order to prevent the spread of Covid-19 protecting the NHS and save lives
“Our officers work incredibly hard to engage and explain the public health message and regulations to prevent such gatherings occurring.
“Last night we received numerous concerns from residents complaining about a large gathering, noise, anti-social behaviour and violence and officers responded to those concerns.
“These gatherings are unlawful, as well as posing a risk to public health and against coronavirus restrictions.
“The violence shown towards officers is totally unacceptable and we will not tolerate it in any form.
“An investigation into the incident is now taking place and those involved will be brought to justice.”