Boris Johnson will warn on Friday that social distancing rules remain essential as pubs and restaurants prepare to open at the weekend for the first time since March.
The prime minister will use a press conference in Downing Street to urge people to support local businesses but to do so carefully.
“They are our local restaurants, hairdressers, libraries, museums, cinemas, and, yes, pubs. They are also our hotels, B&Bs, indeed much of our tourism industry.
“All these businesses and their workers have put in a heroic effort to prepare their venues for this reopening, to work out a way to trade in a way that keeps their customers safe.
“But the success of these businesses, the livelihoods of those who rely on them, and ultimately the economic health of the whole country is dependent on every single one of us acting responsibly. We must not let them down,” he will say.
Lockdown restrictions were tightened this week in Leicester after the city saw a surge in coronavirus infections, and bars and restaurants will remain closed there, along with non-essential shops. Mr Johnson will point to Leicester as a reminder that the virus remains a threat in Britain despite falling numbers of infections, hospitalisations and deaths.
“Just as when we first locked down, we will only succeed in reopening if everyone works together. Because we are not out of the woods yet. The virus is still with us, and the spike in Leicester has shown that. If it starts running out of control again the government will not hesitate in putting on the brakes and reimposing restrictions.
“Anyone who flouts social distancing and Covid-secure rules is not only putting us all at risk but letting down those businesses and workers who have done so much to prepare for this new normal,” he will say.
Meanwhile, schools in England will receive home-testing kits for coronavirus and classes will be kept apart in separate protective bubbles under plans to bring children back to school in September.
A month after the government abandoned plans to bring children back before the summer break, education secretary Gavin Williamson said the new guidance had been developed with public health experts.
“We continue to work closely with the country’s best scientific and medical experts to ensure that both children and staff are always as safe as possible.
“Schools will continue minimising contact between children, including through grouping children together in bubbles and encouraging older children to distance. At a minimum this will mean keeping whole year groups in schools and colleges separate,” he told MPs.
“By the start of the autumn term we will provide all schools and colleges with a small number of home-testing kits, which will be taken home by children or staff who develop symptoms while on site but who would struggle to access a testing centre.”