Police are appealing for drinkers not to become a “drain on the emergency services” as they return to pubs for the first time in more than three months.
Pubs will be allowed to reopen from 6am in England on Saturday and enhanced police patrols will be in place in many towns and cities.
Senior officers have raised concern that queueing and social distancing rules could increase tensions among drinkers, calling the timing and conditions for the reopening a “perfect storm”.
The National Police Chiefs’ Council warned coronavirus still presented “a significant and deadly threat to public health”.
“Don’t be a drain on the emergency services by drinking too much or through anti-social behaviour,” urged chair Martin Hewitt.
“We want everyone to have a good time but please do so safely, responsibly, and with due regard for the public health measures in place.”
Mr Hewitt said local police forces alongside councils and businesses had drawn up plans for their own areas, including increased patrols.
It comes after several police officers were attacked at illegal house and street parties.
A relaxation of the law means that gatherings of 30 people will be permitted in England from Saturday.
Any gatherings above that number, including those inside pubs or visitor attractions, will require a risk assessment and “measures to limit the risk of transmission of coronavirus”.
Separate laws have been imposed in Leicester to limit movement, gatherings and the type of businesses which can remain open in the UK’s first “local lockdown”.
But the new Health Protection Regulations do not prevent the city’s residents travelling to pubs and friends in nearby towns and cities.
The Police and Crime Commissioner for the West Midlands, David Jamieson, said local officers were “praying for rain”.
“It would be helpful if the government listened to people locally and got advice about things like when the lockdown was lifted,” he added.
”When I heard it was a Saturday night, midsummer with three or four months of pent-up frustration - this was a very bad day to choose for the unlocking.
“My view, very strongly, is it could have started earlier this week and we could have led slowly into it.
"We wouldn't have the big bang final, 'Super Saturday' that it's now being called, which has the potential to cause a lot of problems and difficulty.”
In London, the Metropolitan Police urged people to “remain responsible and keep each other safe”.
“Many bars and pubs will be opening under very strict conditions, limiting the number of patrons to help follow social distancing guideline,” said Commander Bas Javid.
“Throughout the weekend, officers across London will be out on duty across London and will be engaging positively with those members of the public who are taking advantage of the ease in restrictions.”
Devon and Cornwall Police said that, as well as the potential influx to pubs, it was seeing a surge in bookings for hotels and self-catering accommodation that can also reopen on Saturday.
Chief Constable Shaun Sawyer said some pubs were planning to impose time limits on drinkers and would offer a “very different experience” to normal.
“All people have a duty to drink responsibly, adhere to social distancing and not fight or commit criminal damage simply because we are coming out of lockdown,” he added.
“We will take proactive action against any drink-related disorder and would ask people to think seriously about their actions.”
Mr Sawyer called for tourists to clean up after themselves, observe social distancing and “not bring more misery upon our communities”.
Local authorities in many areas have been attempting to expand outdoor eating and drinking spaces.
In London's Soho, a food and drink hotspot, traffic will be banned from key streets to make room for diners and drinkers.
The District Councils’ Network said they were “dependent on the public playing their part too, by continuing to exercise maximum care and caution during this challenging period, and drinking responsibly and safely”.