The Government is “anxious” about the Indian variant of coronavirus and is “ruling nothing out”, Boris Johnson has said, as he hinted local restrictions may be needed.

Scientists are keeping a close eye on the spread of the variant across the UK, with new figures from Public Health England (PHE) on Thursday expected to show a big rise in cases.

Speaking at a primary school in Ferryhill, County Durham, the Prime Minister said: “It is a variant of concern, we are anxious about it.

“At the moment there is a very wide range of scientific opinion about what could happen.

“We want to make sure we take all the prudential, cautious steps now that we could take, so there are meetings going on today to consider exactly what we need to do.

“There is a range of things we could do, we are ruling nothing out.”

The Scientific Advisory Group for Emergencies (Sage) is holding a meeting on Thursday to discuss the spread of the Indian variant, amid fears it could have an impact on the Government’s road map out of lockdown.

Bolton has one of the highest rates of the Indian variant in the UK, thought to be mostly concentrated in the under-25s.

A spokeswoman for Blackburn with Darwen Council initially said extra vaccine doses had been secured so all people aged over 18 there could be offered the jab from next week amid rising cases.

But in a statement released later on Thursday, the council said the vaccine would not be widely available to over-18s but only available “in line with Government guidance”.

Asked if local lockdowns were possible, Mr Johnson said: “There are a range of things we could do, we want to make sure we grip it.

“Obviously there’s surge testing, there’s surge tracing.

“If we have to do other things, then of course the public would want us to rule nothing out.

“We have always been clear we would be led by the data.

“At the moment, I can see nothing that dissuades me from thinking we will be able to go ahead on Monday and indeed on June 21 everywhere, but there may be things we have to do locally and we will not hesitate to do them if that is the advice we get.”

Asked if masks and social distancing would be scrapped, Mr Johnson said more announcements would 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 and 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.”

Downing Street also said officials would not “rule anything out” when asked if the Government was considering surge vaccinations to accompany surge testing in areas with spikes of new variants.

The Prime Minister’s official spokesman told a Westminster briefing: “We want to consider all options.

“The meeting is happening with Sage today and should they come out with any further updates on this variant originating in India and the epidemiology in the UK then we will consider it.”

Earlier, Professor Steven Riley, from Imperial College London, said whether the road map for England continued on its planned trajectory was “a Government decision” but suggested the UK was currently in a good place.

He told Times Radio: “I think there’s two key things that have got to be kind of evaluated – if infections go up, how quickly will they go up? But then after that, are they linked to the hospitalisations?

“The top-line Government policy is driven by protecting the NHS, so even if infection starts to go up, we then need to assess whether that’s bringing a lot of new cases into hospitals, and there’s certainly no sign of that at the moment.”

On Wednesday, the European Medicines Agency said it was “pretty confident” that vaccines currently in use would be effective against the Indian variant – a view echoed by some British scientists.

Three types of the Indian variant have been identified in the UK, one of which is a variant of concern.

But Professor James Naismith, from the University of Oxford, said not enough was known to say for sure whether the variant could frustrate the UK’s vaccination programme.

“The vaccines don’t 100% prevent infection for people,” he told BBC Radio 4’s Today programme.

“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.”

Prof Naismith said the variant may spread “way beyond” the local areas where it has been detected, suggesting much wider community transmission of the variant.

“I think we should view it as a countrywide problem,” he said.

“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, adding: “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.”

Elsewhere, Professor Adam Finn, from the University of Bristol and a member of the Joint Committee on Vaccination and Immunisation (JCVI), suggested there was no firm plan for vaccinating teenagers and younger children.

He told BBC Breakfast: “We’ve not really had any discussions yet about immunising teenagers or indeed younger children.

“We don’t have any vaccines authorised for those age groups at the moment.

“But I think it’s also an open question as to whether or not we really will need to do that at this point and, in fact, if we can get really good coverage and a high uptake in the adult population, like Israel, we may find that you see a disappearance, if you like, of Covid throughout the whole population, even without immunising children.

“So that’s yet to be discussed, and it may prove necessary, particularly for teenagers, but it’s not clear that that will be necessary at this point in time.”

He said studies had been completed for the Pfizer vaccine in teenagers and were continuing for the Moderna jab, but it would depend on whether “there really are cases to be prevented”, particularly among schoolchildren.

“If it looks like there’s transmission going on in schools, particularly secondary schools, that would be in favour of doing this, and if there isn’t, then of course that would be in favour of not doing it,” he said.

Prof Finn also said he was not “particularly concerned” that younger age groups may shun vaccines.

He said there was a “very strong sense in UK at the moment that everybody wants to be part of this – to be contributing to the effort and to seeing this pandemic off”.