Three-quarters of UK adults now vaccinated as Boris Johnson suggests lockdown will end on 21 June

The UK has reached the milestone of vaccinating three-quarters of all adults with at least one dose of the Covid-19 jab.

About 39.5 million people have now received a first dose of the vaccine, while 50% of adults – about 26 million people – have also had both doses.

Chris Hopson, chief executive of NHS Providers, described the latest milestones as an “incredible achievement”.

He added: “We know vaccines are breaking the chain between infection rates, hospital admissions and death. But we also know two doses are better than one, particularly in our fight against the Delta [Indian] variant.

“So while there’s a lot to celebrate, we’ve still got a way to go before people have had both jabs. We also know it takes three weeks for doses to be fully effective.

“We urge everyone to get their jabs when they’re offered them.”

It comes after Tuesday's milestone of zero coronavirus deaths recorded in the UK for the first time since the pandemic began.

Mathematical biologist Kit Yates, from the University of Bath, pointed out the 75% figure is related to the adult population – with the total population figure standing at 60%.

He added: "Also worth remembering that second doses are really important, especially in the light of the delta [Indian] variant and we have only given about 40% of the population two doses."

Earlier on Wednesday, health secretary Matt Hancock said confidence in the Covid vaccines has been “sky high” in Britain as he reflected on the rollout.

His comments came amid continuing debate over whether the final stages of unlocking restrictions in England can go ahead later this month due to the spread of the Indian variant – renamed the ‘delta’ variant by the World Health Organization.

Speaking on Wednesday, Boris Johnson once again repeated: “I can see nothing in the data at the moment that means we can’t go ahead with step four of the opening on 21 June.

“But we’ve got to be so cautious because there’s no question… data on infection rates is showing an increase. We always knew that was going to happen, we always said the unlocking steps we have taken would lead to increases in infection.

“What we need to work out is to what extent the vaccination programme has protected enough of us, particularly the elderly and vulnerable, against a new surge.

“I’m afraid the data is just still ambiguous.”

He added: “The best the scientists can say at the moment in their guidance to us is we just need to give it a little bit longer.”

The zero deaths tally reported on Tuesday was hailed by Hancock, though ministers will also have to consider that the announcement came after a bank holiday weekend, so there was likely a delay in the reporting of the figures.

Experts are divided over whether the final stage of easing restrictions should go ahead amid a surge in cases of the new variant first identified in India.

Sir John Bell, professor of medicine at Oxford University, told BBC Radio 4’s Today programme on Wednesday that current figures “don’t look too intimidating” but still need to “play out for a couple of weeks” before the government makes its final decision on whether the reopening can go ahead.

He said: “I think the gain now is, can we get more people vaccinated down into younger, younger age groups to try and stop more transmission.”

Prof Adam Finn, of the Joint Committee on Vaccination and Immunisation (JCVI), said on Tuesday there are still many people who are vulnerable to the effects of Covid, as he warned “the idea that somehow the job is done is wrong”.

Prof Ravi Gupta, a member of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), said a delay of a few weeks could have a significant impact on Britain’s battle against the pandemic, and recommended it should be made clear to the public that it would be a temporary measure based on the surge in cases of the new variant.