Police are asking the public to abide by lockdown restrictions as another warm and sunny bank holiday weekend approaches.
Leaders also called for Muslims to celebrate Eid, which marks the end of the Ramadan holy month, at home over the weekend.
The Metropolitan Police said that it was legal to spend recreational time outside with only those from the same household, or a single member of a different household in England.
“We have been made aware of a number of proposed plans for gatherings this weekend and we can only reiterate the importance of sticking to the government guidelines,” said Deputy Assistant Commissioner Laurence Taylor.
“Restrictions around activities that do not support social distancing remain the same, meaning that group sport, outdoor barbecues or parties, and other gatherings are still not permitted.
“We do not wish to use means of enforcement, but where deemed necessary, officers will take action against those that disregard restrictions.”
Downing Street urged the public to “continue to abide by the social distancing rules”.
The prime minister’s official spokesperson told a Westminster briefing: “We recognise the sacrifices which the public are making but as we head into the long weekend we must all renew our efforts.”
The past week has seen people flock to the coast during a heatwave, sparking concerns around overcrowding in carparks and on beaches.
Dorset Police said there had been a “notable rise in the number of people visiting the county’s beaches, parks, forests and beauty spots” since restrictions were eased on 13 May.
Chief Constable James Vaughan said people had also been violating the law by staying overnight in caravans, tents and holiday homes.
He added: “If too many people flock to these places, social distancing cannot be achieved.
“We’re asking people to think twice about what they’re doing – is it safe and is it fair – and do the right thing. Each of us needs to take responsibility for controlling the spread of coronavirus.”
He warned that RNLI lifeguards are not operating a full service patrolling beaches.
Officials in Cumbria appealed for members of the public not to visit the Lake District.
Colin Cox, the county’s director of public health, said: “I understand that people may feel their individual visit won’t cause a problem, but when thousands of people have the same idea then that has the potential to create genuine issues.”
Derbyshire Constabulary, which polices the Peak District, said local people had been left feeling vulnerable and at risk by “large numbers” of visitors last weekend.
“In many parts of Derbyshire, particularly rural villages, social distancing is difficult with large numbers of visitors,” a spokesperson added.
North Wales Police issued a reminder that under Welsh law people should only exercise in their local area and that restrictions remained more stringent than those in England.
Temporary Assistant Chief Constable Nigel Harrison said: “We’ve continued to see people travelling totally unreasonable distances into north Wales, which is extremely disappointing.”
North Tees and Hartlepool NHS Foundation Trust said coronavirus was “not over yet”, adding: “We can ill afford to become complacent after all the hard work to date
“We all miss our loved ones, we are living through exceptional times, and we recognise the pressures the restrictions bring.”
The Muslim Council of Britain has issued guidance on celebrating Eid in accordance with lockdown measures, as mosques remain closed.
“Though Eid is traditionally marked with congregational prayers in mosques and parks followed by parties amongst families and friends, Eid in the time of the coronavirus will look markedly different,” a spokesperson said.
“Muslims are being encouraged to celebrate Eid in the same way as Ramadan: from home, and virtually with friends and family.”
Greater Manchester Police appealed for members of the public not to travel to the Rusholme area, which normally sees large celebrations, and said there would be a “dedicated policing plan in place”.