Video report by ITV News Correspondent Juliet Bremner
More than 15 million people in the UK have now had a first dose of a Covid-19 vaccine.
The government had set a target of offering a vaccine to its top four priority groups in the UK – the equivalent of 15 million people – by February 15.
Around 67 million people currently reside in the UK, meaning just under a quarter of the population has now received a dose since the first one was given on December 8.
Vaccines minister Nadhim Zahawi confirmed the news on Twitter, writing: "15,000,000! Amazing team We will not rest till we offer the vaccine to the whole of phase1 the 1-9 categories of the most vulnerable & all over 50s by end April and then all adults."
It adds to the positive news from Friday when it was confirmed the coronavirus reproduction number, or R value, had fallen below 1 for the first time since July.
The Prime Minister thanked all those involved in the vaccine rollout - which he described as an "extraordinary feat" - as well as those who had received a first dose. He urged anyone eligible for a jab who had yet to come forward to do so.
Boris Johnson said: “Today we have reached a significant milestone in the United Kingdom’s national vaccination programme.
“This country has achieved an extraordinary feat – administering a total of 15 million jabs into the arms of some of the most vulnerable people in the country.”
He added: “In England, I can now tell you we have now offered jabs to everyone in the first four priority groups, the people most likely to be severely ill with coronavirus, hitting the first target we set ourselves.” He also warned "we’ve still got a long way to go and there will undoubtedly be bumps in the road," but that "after all we’ve achieved, I know we can go forward with great confidence.”
ITV News Health Editor Emily Morgan on why the landmark is an 'extraordinary feat'
There have been more than four million confirmed cases of coronavirus and more than 115,000 deaths in the UK since the start of the pandemic.
NHS chief executive Sir Simon Stevens said: “Hitting this milestone just 10 weeks after the NHS made history by delivering the first Covid vaccination outside of a clinical trial is a remarkable shared achievement. “The NHS vaccination programme is the biggest and fastest in Europe – and in the health service’s history – and that is down to the skill, care, and downright hard work of our fantastic staff, supported by local communities, volunteers and the armed forces. “On behalf of the whole country it’s right to mark this successful first phase with a huge thank you to everyone involved in this extraordinary team effort.”
What happens next?
NHS England said people aged 65-69 can now be vaccinated if GPs have supplies.
Some regions of England have already begun vaccinating the over-65s with their first dose after they reached everyone in the top four priority groups.
Meanwhile, in Wales, First Minister Mark Drakeford said some over-50s there have already begun to be contacted and offered a vaccination as the top four groups had been reached.
A Welsh Government spokesman said it was still proactively contacting anyone in groups one to four “who may have changed their minds or may have been ill or may have, for some reason, not been able to take up the appointment”.
Scotland’s First Minister Nicola Sturgeon has said she expects many in the 65-69 age group to have had their first jab by the middle of this month after the vast majority of older people were vaccinated.
In Northern Ireland, the Department of Health is offering everyone over 65 a vaccine by the end of February as it works its way through priority groups four and five, though it is expected to help the UK meet its overall target.
Have vaccinations impacted on the number of people admitted to hospitals?
NHS England statistics showed there were 101,956 new Covid-19 admissions in January, which accounts for 29% of all admissions between March 2020 and the end of last month.
On the upside, the number of people being admitted to hospital since the middle of last month due to Covid has been on the decline.
As of Friday, 24,352 were still in hospitals in the UK due to Covid, with 3,036 needing ventilation.
However, this fall in numbers is thought to be largely due to tough lockdown measures.
It takes around three weeks for a vaccine to offer its full protection, meaning well below 15 million people are protected.
Will this allow lockdown to be lifted?
As a growing number of people are being vaccinated and the amount of people being admitted to hospital falling, there will be renewed calls for a lift lockdown.
To further reduce the chances transmission of Covid variants, those arriving in England from 33 countries need to quarantine for 14 days.
Downing Street has said it can add extra hotel rooms for quarantine “as required”, after signing contracts for 4,600 rooms so far.
The tourism sector in Wales could be able to reopen by Easter as part of the country “slowly and cautiously” easing restrictions if infections continue to fall.
First Minister Drakeford said the Welsh Government was speaking to the tourism and hospitality industries in Wales about “what might be possible”.
But Mr Drakeford warned that any reopening would be dependent on infection levels of Covid-19, the impact on the health service and the success of the vaccination programme.
Boris Johnson’s “road map” for easing England’s third national lockdown is due out in a week, with March 8 earmarked for a wide reopening of schools.
Downing Street confirmed that the plan to ease the lockdown will be published on February 22 after alarm among some Conservative MPs that the date may slip back.
On Wednesday, chief scientific adviser Sir Patrick Vallance said it was crucial to ease restrictions “cautiously” and rejected the setting of deadlines.
“The virus isn’t going to be particularly interested in dates,” he said at a Downing Street press conference.