Drunk people are unable to properly socially distance, the chairman of the British Police Federation has said as pubs reopened in England for the first time since lockdown.
John Apter said it was "crystal clear" revellers would not adhere to the one metre plus rule as restrictions were eased yesterday.
England's Chief Medical Officer Professor Chris Whitty said the pandemic "is a long way from gone" and urged the public to follow social-distancing rules as pubs and restaurants reopened.
But images from London's Soho showed packed streets into the early hours of this morning.
Mr Apter, who was on shift in Southampton where he dealt with "naked men, happy drunks, angry drunks, fights and more angry drunks", said: "What was crystal clear is that drunk people can't/won't socially distance.
"It was a busy night but the shift managed to cope. I know other areas have had issues with officers being assaulted."
There was disorder in north Nottinghamshire too, where four people were arrested and several pubs decided to close after alcohol related anti-social behaviour.
A major easing of lockdown measures in England saw pubs, restaurants, hairdressers and cinemas opening their doors again under modified social distancing regulations.
Prime Minister Boris Johnson and government experts urged people to stick to the rules to avoid creating a second wave of coronavirus.
Health Secretary Matt Hancock said the vast majority of people who went out on 'Super Saturday' were "doing the right thing" and following social distancing.
Speaking on Sky's Ridge On Sunday, Mr Hancock said: "Well I think that from what I've seen, although there's some pictures to the contrary, very, very largely people have acted responsibly."
He added: "So overall I'm pleased with what happened yesterday. It was really good to see people out and about and largely, very largely social distancing."
Mr Hancock said "the large proportion of people, the vast majority of people are, I think, doing the right thing".
He added: "But of course we'll take action when we need to when... if the minority break the rules."
On those who did not social distance, Mr Hancock said: "Well we'll of course keep this very closely under review, and you've seen for instance in Leicester but also in other places that we don't shirk from bringing in more drastic measures if that is what's needed to control the virus."
Rafal Liszewski, a store manager at Clonezone on Soho's Old Compton Street in London described crowds in the area last night after pubs were allowed to trade again as "out of control".
"Saturday started very easy. But you could feel tension in the air," the 36-year-old said.
"Around 1pm crowds started to arrive ... quickly everything got out of control and by 8-9 pm it was a proper street party with people dancing and drinking.
"Barely anyone was wearing masks and nobody respected social distancing ... to be honest with that many people on one street it was physically impossible."
Mr Liszewski estimated there was between 2,000-3000 people on the street, but his shop was only allowing seven customers at a time.
Speaking on Friday, Prof Whitty said: "None of us believe, and I'm sure nobody watching this believes, this is a risk-free next step. It is absolutely not, that is why we have to be really serious about it.
"There's no doubt these are environments whose principal job it is to bring people together, that's a great thing to do socially, but it's also a great thing from the virus's point of view.
"Therefore, we do have to have a really clear and really disciplined approach to try and maintain social distancing whilst also enjoying pubs."
Mr Hancock said the government's message to the public is "enjoy the new freedoms, but do so safely".
Asked when the British government should begin learning lessons from its response to the pandemic, Mr Hancock said: "Well we are learning all of that all of the time, looking at what works and what needs improvement."
He added: "And my overriding message to people is yes, enjoy the new freedoms, but do so safely following social distancing. It is so important, and even the basics like washing your hands.
"We have got this virus getting right under control, the number of new infections is under 600 on the last data, so it is really coming down in terms of the number of positive cases that we're finding and that is good news, but we've just got to have the resilience and resolve to stick at it and to be very careful in how we enjoy those new freedoms."
Mr Hancock said: "Yes, go out there and enjoy summer and get out and enjoy the things that we love, that we've been able to lift the restrictions on, but do so safely.
"And there are two parts to that - enjoy summer safely. And it's a really important message and I think it's one that the vast majority of people understand."