Hundreds of revellers defied lockdown rules to gather at a street party in north-west London before it was broken up by police.
Scotland Yard said 11 officers were assaulted and five arrests were made as around 500 people gathered in Harlesden on Tuesday evening.
Images on social media showed music playing loudly as revellers, packed tightly together, danced, drank and set off fireworks while a police helicopter flew overhead.
Nearby residents complained that the noise kept them up until the early hours on Wednesday, before police finally left the scene on the Church Road Estate just before 4am.
Clive McBride, 55, who lives nearby, told the PA news agency: “I first thought something was up when I saw loads of people outside at about 8pm, neighbours were out on the road and I could hear a police chopper flying above.
“I went down to see what was happening and there were people everywhere, drinking, singing and dancing, and completely ignoring the rules we are all meant to follow.
“No-one paid any attention to two-metre distancing, they were like sardines, it was crazy.
“Just before 1am they started shooting off fireworks, but what most people complained about was the noise of the helicopter, I don’t think many people slept.”
Tarquin Ramsay, 24, who lives a mile away, said: “It’s a bit dumb to throw a block party considering we are in Brent, which has been one of the hardest hit areas by the virus in the country.”
Metropolitan Police officers were initially called at 6.45pm on Tuesday following community concerns that around 60 people were gathered at an unlicensed music event around the Gifford Road area.
A larger group of around 500 people later gathered in Paulet Way, before officers began to disperse them.
Eleven officers were assaulted and received minor injuries when a small minority refused to leave, the force said.
Three arrests were made for assaulting police officers, one for affray and one for attempted grievous bodily harm and dangerous driving. All remain in custody.
Chief Superintendent Roy Smith, Commander for North West London, said: “Our officers are working hard to engage with the public to reinforce the public health advice on social distancing and large gatherings – overwhelmingly our local communities have been supportive and responded to this approach and we thank them for that.
“To the very small minority who chose to break the law last night and who were not from the local area, I am clear: you do not reflect the communities of Brent and we will take appropriate action.
“Local residents should be reassured we will be increasing our patrols in the area following the incident.”