The government's scientific advisors are holding an urgent meeting today to discuss the growing threat from the Indian Covid variant.
The meeting, first reported by i news and confirmed by Boris Johnson, comes after the number of B1.617.2 variant cases in the UK almost tripled to 520 as of May 5.
The newspaper claims new figures today could show the number of cases has tripled again in the last week to around 1,500.
A member of the committee claimed “a delay is possible” to the final phase of lockdown easing in England - which is meant to abolish all legal social distancing rules from June 21. SAGE meet regularly.
Boris Johnson today admitted “we are anxious about it - it has been spreading”.
- Read an updated version of this story here.
The PM said “we’re ruling nothing out” and “there are meetings going on today to consider exactly what we need to do.”
The PM insisted “at the moment I can see nothing that dissuades me” from thinking the final stage of ending lockdown rules can happen on June 21.
But he suggested the return to “normality” could slip to a later date if the Indian variant “takes off”.
Asked if masks and social distancing were going, Boris Johnson said more announcements will be made before the end of the month.
He added: "I think we have to wait a little bit longer to see how the data is looking but I am cautiously optimistic about that.
“Provided this Indian variant doesn't take off in the way some people fear, I think certainly things could get back much, much closer to normality.”
But Tory minister James Cleverly today refused to rule out delaying the end of lockdown beyond June 21.
Mr Cleverly also refused to rule out the prospect of local lockdowns in areas like Bolton, where the variant is believed to be spreading.
But one expert today warned the spread of the coronavirus Indian variant should be viewed as a nationwide problem.
Professor James Naismith, from the University of Oxford, said the variant may spread "way beyond" the local areas where it has been detected.
Prof Naismith, who is also a director at the Rosalind Franklin Institute, said: "I think we should view it as a country-wide problem.
"It will get everywhere. We keep learning this lesson, but we know that this will be the case."
Prof Naismith said he did not believe local restrictions would work to contain the variant.
He told BBC Radio 4's Today programme: "When we tried locally having different restrictions in different regions that didn't really make any difference.
"So I don't think thinking about a localised strategy for containment will really work."
He added: "The vaccines don't 100% prevent infection for people. What they do, is they almost 100% prevent hospitalisation and serious illness.
"We don't know enough to know yet whether the Indian strain will behave differently than that. So even the regular virus can infect people who have been vaccinated and sometimes you do get reinfection.
"And the very, very large number of cases in India mean things that are rare will be detected."
Boris Johnson is expected to be asked for more details of the Covid-19 public inquiry when he faces the TV cameras.
The Prime Minister is due to visit a school in Co Durham where he is set to face questions over why the probe will not be launched until next spring.
Asked about a possible delay to the June 21 easing, Foreign Minister James Cleverly told Sky News: “Scientists on SAGE will make assessments, they will report that to government, and we will make decisions based on the data, the evidence they provide.
“The Prime Minister and the Health Secretary have always been clear that the easing of restrictions which allows us to get back to normality will be done at a pace and in a way that is safe.
“We will always be driven by the data.”
