Boris Johnson has blamed a failure of people to come forward for booster jabs for the slow rollout of the programme, calling it “a demand issue”.
The NHS and the department of health are both in the firing line for the low number of vaccinations – with Labour claiming two million eligible people have yet to receive an invitation.
But the prime minister insisted there is adequate supply, saying: “It’s a demand issue. We really urge people to come and do it.”
He acknowledged case rates are “high” and are rising, after almost 50,000 new infections are recorded each day across the UK.
But he insisted they are “within the parameters of what the predictions were” from government advisers when the lifting of the lockdown was completed in the summer.
People aged over 50 and vulnerable groups who received their second vaccination six months ago – and whose immunity is waning – are now eligible for a booster dose.
But, in stark contrast to the original jabs programme, GP surgeries are not involved and it has been left to the NHS to organise centrally, as it wrestles with a huge and growing patient backlog.
Labour accused the prime minister of attempting to shift the focus from his government’s failure to deliver the jabs so badly needed.
“This is a typically insulting comment from Boris Johnson trying to deflect from his stumbling vaccination programme,” said Jonathan Ashworth, the shadow health secretary.
He warned the booster programme is “stalling” and that, at the current rate, it would not be completed until next March – long after the expected winter peak for infections.
On a visit to mark Northern Ireland’s centenary year, Mr Johnson also commented on Ali Harbi Ali appearing in court charged with the terrorism-related murder of former Conservative MP David Amess.
“I hope the family of David Amess and all those who love him will get the justice they deserve as fast as possible,” he said.
“What we must not do is be intimidated by this appalling murder into changing the way we conduct our parliamentary business or the way we work in our constituencies – which I think is the last thing that David Amess would have wanted.”
The prime minister called for the dispute with the EU over the post-Brexit Northern Ireland Protocol need to be “flushed out pretty fast”, as talks continue with Brussels.
And he defended the move to end all Troubles-era prosecutions in Northern Ireland, after the death of Army veteran Dennis Hutchings while on trial over a 1974 shooting.
The Council of Europe has warned of possible breaches of international law, including the European Convention on Human Rights.
But Mr Johnson said: “What we want to do is to try to tell the story of what has happened in The Troubles and to try to bring as much reconciliation and understanding as possible.
“But to bring an end to the endless cycle by which people are being brought to court with no new evidence for things that have been tried and heard many, many years ago.
“That is the thing that I think people want to end, and we want to find a solution that brings people together, allows people to grieve, but also allows people to move on.”
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies