Police have discovered more than 70 people partying on a boat in west London in breach of coronavirus lockdown measures.
Officers were called to Volt Avenue, North Acton shortly after 11pm on Saturday to reports of a large gathering on a moored boat.
The group was dispersed and a total of 72 people were reported for the consideration of fixed penalty notices of £800 for attending an indoor gathering of more than 15 people in breach of the coronavirus regulations.
The organiser was identified and reported for consideration of a £10,000 fine.
Detective Chief Inspector Thomas Bowen, of West Area, said: "This was a blatant breach of the coronavirus rules that are in place to save lives and protect the huge pressure on the NHS.
"All the people who attended this event, which appears to have been organised on social media, have quite rightly been reported for the consideration of fines."
It comes after police issued fines to a slew of "selfish individuals" who breached coronavirus lockdown rules this weekend - including people who attended a gym, a hotel and a house party.
Eighteen "reckless revellers" were among those breaking the rules on Saturday and were fined almost £15,000 after officers interrupted a house party, Essex Police said.
Meanwhile, in Merseyside, police discovered around 200 people partying in a hotel in the early hours of Sunday morning and broke up a gathering of nearly 20 people in a gym on Saturday night.
An Essex Police spokesman said officers attended a house in Sewardstonebury at around 5pm on Saturday following reports of a party.
Officers were initially refused entry by people inside who claimed to be making a music video.
The 18 individuals inside - 17 from London and one from Essex - were fined £800 each following the introduction of higher penalties, the force said.
Deputy Chief Constable Pippa Mills said: "These selfish individuals not only have no regard for their own safety, but they clearly didn't give a second thought for the safety of the local community, the police officers who had to attend to deal with their reckless behaviour or the NHS who are under unbelievable pressure."
An investigation is under way to establish whether two previous unlawful gatherings at the vacant, rented property were organised by the same person, police said.
In Merseyside, 19 gym-goers who were found in Shred Fast Gym in Aintree at 10.30pm on Saturday were also handed fixed penalty notices this weekend.
They were found not wearing PPE or social distancing, and had travelled from areas including Billinge, Widnes, Wirral and Southport, the force said, which subsequently reported the business owner to the local authority.
At 3.15am, officers found around 200 people at the Richmond Hotel in Liverpool city centre where four parties were going on, the force said.
Police said 13 fixed penalty notices were issued, 11 documented warnings were given and everyone who was not a legitimate guest at the hotel was removed.
One woman was arrested on suspicion of breaking COVID rules and two counts of assaulting a constable.
Chief Superintendent Matt Boyle said: "This sort of behaviour is unbelievable and unacceptable and officers should not be confronted with abuse and violence when attempting to uphold the law, which most people are rightly abiding by."
New coronavirus regulations came into force in England at 5pm on Friday - which include fines of £800 for people caught at house parties with groups of more than 15 people and will double after each offence, up to a maximum of £6,400 for repeat offenders.