LONDON — Pubs opened for drinks indoors, lights went on in theaters and airports buzzed with a steady stream of travelers on Monday, but the latest easing of Covid-19 restrictions in England was accompanied by growing fears that a variant of the virus could delay a full return to normality.
The lifting of a wide range of coronavirus rules Monday coincided with a small but worrying spike in cases of a variant, first identified in India, that threatens a lockdown-lifting road map frequently described by Prime Minister Boris Johnson as “cautious but irreversible.”
Already, the second part of that pledge is sounding less secure than it once seemed. In recent days the authorities have scrambled to ramp up testing and inoculation in parts of the country seeing a sharp rise in cases of the more transmissible variant. More than 6,200 people were vaccinated over the weekend in Bolton, a badly hit town near Manchester in the northwest of England.
The opposition Labour Party has accused Mr. Johnson of bringing on the trouble by delaying a decision to close borders to flights from India last month, while government scientific advisers have expressed their concerns about moving too fast to remove curbs.
Even Mr. Johnson, who is normally only too keen to ridicule pessimists as “doomsters and gloomsters,” urged Britons to be cautious in the face of the threat from the new variant, saying that there was a risk of “significant disruption” to plans for easing rules.
Nor did Mr. Johnson plan to visit a pub or restaurant on Monday to celebrate in front of the TV cameras, his office said.
In recent weeks Mr. Johnson has been able to claim credit for a highly successful vaccine program that, combined with lockdown restrictions, has cut cases and death rates to a fraction of their peak numbers. That has enabled England to start easing the burden on many of the parts of the economy that were worst affected by a lockdown in January.
Under the changes that came into force on Monday, pubs and restaurants can serve indoors as well as outside, people can hug each other and mix inside their homes in limited numbers.
Museums, theaters and movie theaters, sports stadiums, hotels and indoor playgrounds opened their doors again in England, though Scotland, Wales and Northern Ireland all have slightly different timetables and conditions for relaxing rules.
A legal ban on all but essential foreign travel ended too, though travelers to any other than a small number of destinations will have to quarantine on their return.
Altogether, that represents the first real breath of freedom for many in England since the third national lockdown was declared in early January. Though restaurants and pubs have been able to serve food and drink outdoors for several weeks, the weather has been unseasonably cold and often rainy, leaving many diners and drinkers shivering in damp beer gardens.
While the government will fight hard not to have to reverse the changes introduced on Monday, there are growing doubts about whether it can proceed with the next stage of the road map. That change, scheduled to take place on June 21, would scrap almost all remaining restrictions.
But with a surge of cases in some communities, including Bolton, the government is refusing to rule out any measures, possibly including the imposition of new restrictions on specific Covid-19 hot spots.
“We must be humble in the face of this virus,” the health secretary, Matt Hancock, told Parliament on Monday, adding that there were now 86 areas with five or more cases of the variant whose higher transmission rate “poses a real risk.” While the overall case numbers, at 2,323, remain low, they have been multiplying rapidly.
Mr. Johnson continues to hear criticism for failing to clamp down fast enough on travel from India, even sparing it for some weeks after placing restrictions on travel from Pakistan and Bangladesh.
Under Britain’s travel system those arriving from “red list” countries that are deemed high risk are required to quarantine in hotels.
“Our borders have been as secure as a sieve,” said Jonathan Ashworth, who speaks for the opposition Labour Party on health issues. “The delay in adding India to the red list surely now stands as a catastrophic misstep.”
Pakistan and Bangladesh were red listed on April 9 but India was not added until April 23, and Mr. Johnson’s critics have suggested he was reluctant to upset India’s prime minister, Narendra Modi, with whom he is trying to strike a trade deal.
Mr. Hancock rejected that claim and said that significantly more people arriving from Bangladesh and Pakistan tested positive for Covid-19 than those arriving from India. In Parliament on Monday he accused the Labour Party of selective hindsight, saying that last month the Indian variant had not been identified as one of concern.
But some experts believe that the government should have reacted faster to the emergence of the variant. “Many of us in the U.K., we’re appalled at the huge delay in classifying it as a variant of concern,” said Peter English, a retired consultant in communicable disease control.
“You can’t stop diseases from crossing boundaries — they inevitably will,” he said, adding: “But you can slow the spread, and while that’s happening, you can learn more about it.”
Mr. English said that there was not yet enough data available to determine how effective vaccines are in combating the variant, but added that more financial support should be given to those on low incomes who need to self-isolate.
In general, Britons are being offered vaccination based on their age, with those oldest treated first. Appointments are to be extended this week to 37-year-olds, Mr. Hancock said.
However, in areas affected by the Indian variant, health chiefs appear to be offering vaccines to some younger people, using the flexibility in guidelines that, for example, suggest the vaccination of those living in a multigenerational household.
On Monday, Mr. Hancock also said that of 19 cases in Bolton hospitals, most of the patients were eligible for vaccination but had not had one. That prompted a debate in and beyond Mr. Johnson’s Conservative Party about whether the lifting of lockdown restrictions should be reversed to protect people who refuse a vaccine.
Andrew Lloyd Webber, composer and theater impresario, told the BBC that vaccine hesitancy was not only foolish but selfish. He added that he could not reopen his shows without an assurance that all restrictions would be eased as planned from June 21, allowing for full seating without distancing.
“I just feel so strongly at the moment, particularly the people who are not getting vaccinated and everything, just how selfish it is because so many people depend on this June 21 date, they really depend on it,” he said.
Megan Specia contributed reporting from London.