Pubs, cafes and restaurants could start to reopen in summer, providing they are able to operate social distancing measures.
Boris Johnson said the hospitality industry could begin trading again as early as July, under strict conditions and as long as the spread of coronavirus continues to be brought under control.
In his address to the nation on Sunday setting out a “roadmap” for the easing of lockdown, the PM said: “If, and only if the numbers support it, we will hope to re-open at least some of the hospitality industry and other public places, provided they are safe and enforce social distancing.
“Throughout this period of the next two months we will be driven not by mere hope or economic necessity. We are going to be driven by the science, the data and public health.
“And I must stress again that all of this is conditional, it all depends on a series of big ifs.”
Johnson said the entire country must “continue to follow the advice, to observe social distancing, and to keep that R [rate of infection] down”.
Schools, nurseries and non-essential shops will remain closed until at least June 1, with a phased return planned for pupils, starting with young primary-aged children.
He gave five phases of a “Covid alert level” that will be primarily influenced by the rate of transmission, or R, which he said is between 0.5 and 0.9 “but potentially just below one”.
“No, this is not the time simply to end the lockdown this week,” he said. “Instead we are taking the first careful steps to modify our measures.”
Cumbria Tourism, the board covering UK holiday hotspot the Lake District, tweeted it was “shocked” at the PM’s announcement and said its attractions would remain closed.
But the National Trust said it was reviewing plans for reopening sites following the speech.
“Following the prime minister’s broadcast outlining the government’s gradual road map out of lockdown, we will begin to review its effect on our reopening plans,” a spokeswoman said.
Last week, the trust said it was working on plans to reopen sites, which have been shut to the public since March 24.
Johnson urged those who are unable to work from home, such as construction workers and manufacturers, to return to work, as part of the first phase of reopening the economy.
But Trades Union Congress general secretary Frances O’Grady said Johnson’s statement would cause “a lot of confusion and anxiety”.
“The government still hasn’t published guidance on how workers will be kept safe. So how can the prime minister – with 12 hours’ notice – tell people they should be going back to sites and factories? It’s a recipe for chaos,” she added.
“Unions want to support a safe return to work so we can start rebuilding Britain. Government must provide clear direction to workers and business by introducing tough new rules on workplace safety.
“That’s the only way to build public confidence in their plans and get the economy moving.”
Labour leader Sir Keir Starmer said the government’s latest strategy was not based on political consensus.
He told Sky News: “What I really wanted, I pushed them on this last week, I said ‘build a consensus around the plan before you deliver the plan’ that’s been delivered this evening.
“Because I think the public are very scared and anxious about what comes next. They want reassurance.
“And if they can see political parties, employers, England, Wales, Scotland, Northern Ireland all broadly on the same page – that helps with reassurance and confidence.
“But I’m afraid we’ve arrived tonight without that.
“Now, you know, that’s a duty them, on all of us, to see whether we can provide that going forward. But that basic consensus that I was arguing for, I don’t think is there tonight.”