LONDON — Concerned by the spread of a new coronavirus variant, Prime Minister Boris Johnson of Britain was on Monday preparing to announce a delay of up to four weeks to the lifting of Covid-19 restrictions in England, effectively postponing a long-awaited moment described in the news media as “freedom day.”
In a statement scheduled for Monday afternoon, Mr. Johnson is expected to say that rising cases of the Delta variant, first detected in India, make it impossible to remove the remaining curbs on June 21, as had been envisioned, because a rapid growth in infections would pose a risk to the health service.
The decision is a political setback for Mr. Johnson, an instinctive libertarian, who resisted imposing lockdowns in the first place and whose swift vaccination rollout has provided an exit route from the crisis.
Under the current rules, pubs and restaurants can operate but with limited capacity and there are limits on gatherings such as weddings. Theaters and nightclubs are closed.
Andrew Lloyd Webber, the producer of musicals including Cats, has pledged to reopen his theaters this month “come hell or high water,” telling the Telegraph newspaper that he was willing to be arrested.
It was unclear whether Mr. Johnson would allow any of the remaining restrictions to be eased.
But, having already been forced to impose three lockdowns, Mr. Johnson now says he wants any moves out of them to be “irreversible” and at the weekend all but confirmed the delay when he said that Monday’s decision would be driven by caution.
Although Britain is one of the world’s leaders in vaccination, the government’s plans have been thrown off course by the growth in cases of the Delta variant, which British scientists have reported to be even more transmissible than the variant that swept across the country over the winter.
Though case numbers are still relatively low — 7,490 new ones were reported on Sunday — they have risen rapidly in recent weeks and the Delta variant now makes up the overwhelming majority of all coronavirus cases in England.
Critics who say that the government is being too cautious note that as lockdowns were eased, cases were always going to rise. And as variants continue to spread, they argue, policies need to account for the virus’s becoming endemic in the population, for example by focusing more effort on tackling hot spots.
So far, the increase in cases in Britain has not translated into large-scale hospitalizations and deaths.
Still, on Sunday, 187 new hospitalizations were reported and the government says that it is not yet clear that the vaccination campaign is far enough along to sever the link between case counts and serious illness.
Government officials have argued that a delay in easing all restrictions would provide more time to ramp up vaccinations and to deliver the second doses that make the vaccine more effective against the Delta variant.
“Clearly, what you’ve got is a race between the vaccines and the virus, and the vaccines are going to win,” Mr. Johnson told the BBC on Sunday. “It’s just a question of pace.”
For days, ministers have been debating whether to opt for a four-week delay or to limit it to two weeks. One alternative is to set out a four-week span but with a review halfway through.
Since people can still go to pubs, restaurants and stores, albeit with social-distancing restrictions, the impact of the delay will be somewhat blunted.
But for businesses operating at a loss, and those that remain closed, the decision will be another bitter blow after a traumatic year.
The Night Time Industries Association called the delay “catastrophic,” noting that businesses such as nightclubs had already spent millions preparing to reopen.