Scientists fear the final stage out of lockdown could be delayed due to a surge in cases of the Indian Covid variant in the UK, according to reports.
The final stage of the government's roadmap for easing lockdown restrictions is scheduled for June 21 – when it is hoped all limits on social interactions will be lifted.
But experts advising the government believe this date could now be pushed back, reports i news.
New official figures set to be released tomorrow are expected to confirm that UK cases of the highly transmissible Indian Covid variant have more than tripled in a week.
Members of the Scientific Advisory Group for Emergencies (SAGE) will assess the threat at meeting on Thursday, Mirror Online reports.
A member of the committee told the i news that “a delay is possible” in relation to the final phase of lockdown easing in England.
However, they added that Step 3 on Monday, which includes pubs and restaurants being able to welcome customers inside, would go ahead as planned.
The Prime Minister has warned the B1617.2 strain, currently among three running rampant across India, is "of increasing concern" in Britain.
Surge testing has been introduced in the likes of Bolton, Greater Manchester, to help stem the spread of cases.
In areas at risk, school children may be told to continue wearing face masks after the restriction is dropped in England from Monday.
The May 17 easing also includes up to six people from other households allowed to mix indoors and the lifting of the non-essential foreign travel ban.
COG-UK, the cross body group of experts tasked with keeping track of new mutations, has identified 1,723 cases of the Indian variant.
If this figure is confirmed by Public Health England in tomorrow's weekly update, it would be treble the 520 figure from seven days before.
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Ministers have not ruled out re-introducing local lockdowns in areas where the variant of concern is increasing.
Addressing the Commons on Wednesday, Mr Johnson said “the threat of this virus remains real and new variants pose a potentially lethal danger".
He said this includes the Indian variant "which is of increasing concern here in the UK".
"So caution has to be our watchword," he added.
Across the UK, the weekly average of all Covid infections rose for the third day in a row on Wednesday.
Asked whether local lockdowns could return, Environment Secretary George Eustice told Sky News: "We can’t rule anything out but our plan that has been set out by the Prime Minister and the reason we are being incredibly cautious about exiting lockdown is because we want this to be the last."
The Mirror contacted Downing Street for comment.