Two Metropolitan Police officers were injured while breaking up an "incredibly selfish" party involving about 200 people in the affluent London borough of Chelsea.
Police said that officers responded to reports of a mass gathering taking place at an address on Beauchamp Place at 3.30am on 17 January.
Several units had to be deployed to the venue where more than 200 people were attending the illegal party.
As the units worked to clear the crowd pouring into the street, guests became hostile, pushing through officers in an attempt to flee and avoid fines.
The Met Police said two of their officers were injured as a result.
The force then put a cordon in place at the entrance of the party to detain a large group of remaining guests inside.
Officers issued around 30 fixed penalty notices to partygoers and are preparing a three-month closure order for the establishment’s owner, who was previously fined £1,000 for lockdown breaches.
Supt Michael Walsh said: "Attending or organising such parties during this critical period is an incredibly selfish decision to make.
“My officers continue to work incredibly hard to uphold Covid legislation in order to keep people safe. While the majority of breaches have been resolved without incident, it deeply saddens me that some individuals have chosen to assault police officers who are simply doing their part in the collective battle against this deadly virus.
“We will absolutely not tolerate assaults on police officers. It goes without saying that anyone who harms an emergency worker will face the full force of the law.”
The party came as one of several illegal gatherings recently reported in the borough by Scotland Yard.
On 20 December, police shut down an illegal gathering at a commercial property on Montpelier Street, which has now been closed for three months.
On January 16, police raided a venue on Harrow Road near Ladbroke Grove, finding 30 people socialising in close proximity. The owner is now facing a £10,000 fine.
On Thursday, police also broke up a wedding party at the Yesodey Hatorah Senior Girls' School in north London, saying around 150 guests were attending.
It comes as the country continues to battle with a devastating second wave of coronavirus.
Police forces around the country have been shutting down illegal gatherings and cracking down on lockdown breakers.
Home Secretary Priti Patel this week announced a new £800 fine for people caught attending lockdown parties.
Kensington and Chelsea councillor Emma Will said: “These businesses refused to adhere to the Covid-19 restrictions, disturbing local residents and placing their own customers and the wider public at significant risk again and again.
“Where breaches like this occur our council officers will work with the police, using the full range of both our powers to tackle those who break the law. Most businesses are doing the right thing to protect their local communities during the pandemic but those who flout the rules will face consequences.”