The spread of the Indian Covid-19 variant could lead to the return of local lockdowns, UK ministers have acknowledged.
The rise in cases of the highly transmissible variant of concern risks the next stage of England’s road map out of lockdown, currently pencilled in for June 21st, being delayed.
But if outbreaks are limited, ministers could opt instead to push ahead with the reopening while keeping some areas under restrictions in an echo of the controversial tiers system.
UK cabinet minister George Eustice still wants the June 21st measures, which would see most remaining restrictions scrapped, to go ahead but said: “We can never rule out that there may have to be a delay.”
Asked whether it was possible for parts of the country to enjoy new freedoms on June 21st while others are kept under restrictions, Mr Eustice said: “That would be an option and we cannot rule anything out, obviously, at this stage.”
But he told Sky News the “preferred outcome” would be to drive up vaccination rates in areas where there have been outbreaks.
Bolton, Blackburn with Darwen and Bedford are the areas ministers are most concerned about.
An estimated 64.1 per cent of over-16s in Bolton had received a jab as of May 9th, with 33.5 per cent having had both doses.
In Blackburn the figures were 60.6 per cent for one dose and 28.8 per cent for two and in Bedford the data showed 66.3 per cent had received a single jab and 32.3 per cent both doses.
Across England 64.8 per cent had received first doses and 33 per cent both jabs as of May 9th.
Steven Riley, a professor of infectious disease dynamics at Imperial College London, told BBC Radio 4’s Today programme: “The timing of the variant is bad in some ways because it is happening as we are trying to open up and taking a significant step in relaxation.
“It is good in other ways because we are at very low levels of infections, cases and hospitalisations.
“This is the point in the road map where we would have expected perhaps an increase in infections anyway.
“I think that most people would be expecting an increase, it is just the degree of the increase.”
Professor Gabriel Scally, a member of the UK's independent Sage group of scientists, told Sky News “we should be throwing the kitchen sink at this” in places like Bolton and Blackburn to reduce infection.
He said vaccinating younger age groups, thorough contact tracing and support for people to self-isolate was needed.
“We also need to stop the importation of it and that means better border controls, a proper quarantine system,” he said.
“We’ve been let down badly by the large number of cases that the UK has imported of this dangerous variant that was first identified in India.”
In the Commons on Monday, UK health secretary Matt Hancock said there were now 2,323 confirmed cases of the Indian strain in the UK, with 86 local authority areas recording at least five.
Worst hit have been Bolton and Blackburn with Darwen, where it is now the dominant strain with a total of 483 cases across the two areas, followed by Bedford.
The authorities have responded by deploying “surge” vaccinations and testing in virus hotspots in an attempt to curb the spread of the disease.
However, Mr Hancock expressed frustration that of the 19 hospital cases in Bolton, the majority had not had the vaccine, even though they were eligible.
Despite concerns the Indian variant is even more transmissible than the dominant Kent strain, the latest easing of lockdown restrictions went ahead as planned on Monday across most of England, Scotland and Wales.
It meant pubs and restaurants were able to welcome customers inside while people were able to socialise indoors and to hug family and friends outside their own households.
In the North, a decision is due this week on whether the next stage of easing can go ahead as planned on Monday.
