More than 15 million people in the UK have now had their first coronavirus vaccine, in what Boris Johnson described as a "significant milestone".
The PM hailed the "extraordinary feat", reached just over two months after the first jab was given on 8 December.
It comes as the government is expected to announce on Monday it has met its pledge to offer a jab to everyone in the top four priority groups in the UK.
The rollout is now being expanded to over-65s and the clinically vulnerable.
Wales has also met the target.
But "no-one is resting on their laurels," Mr Johnson said. "We've still got a long way to go to. And there will undoubtedly be bumps in the road. But after all we've achieved, I know we can go forward with great confidence."
Sunday's daily coronavirus figures show 15,062,189 people have now received an initial vaccine dose - after 505,362 first jabs were given out on Saturday.
A further 258 people in the UK have died within 28 days of a positive Covid test, taking the death toll by that measure to 117,166. Fewer deaths tend to be reported on Sundays, due to a reporting lag over the weekend.
There were 10,972 new cases reported, bringing the total number of recorded infections to 4,038,078.
'Route to freedom'
NHS England chief executive Sir Simon Stevens said the 15 million milestone was a "remarkable shared achievement" - reached 10 weeks after the first vaccine was administered in the UK.
"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," he said.
Health Secretary Matt Hancock said it meant one in every four adults was now "starting to receive protection from this dreadful disease".
But he cautioned: "There is so much more to do and I urge anyone eligible to step forward and take up their appointment. The vaccine is our route to freedom - we will beat this virus jab by jab."
So far the vaccination programme has been aimed at the top four priority groups, including NHS frontline staff, care home residents and workers, over-70s, and people deemed clinically extremely vulnerable.
These groups have accounted for 88% of the UK's Covid-19 deaths so far, according to the Department of Health and Social Care and are estimated by the JCVI to be some 15 million people.
A small number of the 15 million to receive a jab will have been outside these priority groups.
Ruth Rankine, director of the NHS Confederation's PCN Network of GP practices, paid tribute to the "incredible accomplishment" but added that "until everyone is protected, no one is protected".
"There is still work to do to administer first doses to all the remaining people from the first four cohorts, as well as moving down the cohorts until everyone has at least been offered a jab, not to mention beginning the work of administering second doses," she said.
Labour's shadow health secretary, Jonathan Ashworth, said ministers needed to "lock in the gains of vaccination" and introduce further measures to reduce the spread of the disease.
This included increased financial support for those who have to self-isolate, updated guidance on masks and help to make workplaces Covid secure.
It is undeniable the vaccine programme has overall been a success - only Israel and the United Arab Emirates have done more jabs per head.
But as well as pushing ahead with the under-70s, efforts need to continue to reach out to those not yet vaccinated in these first groups.
There have been reports of housebound patients still waiting, while some have questioned whether enough has been done to reach out to those who have concerns and have not taken up the offer.
The fear is uptake may be lowest in some of the most vulnerable communities and that risks widening health inequalities.
People will also ask what this means for unlocking. Those offered the jab account for around five in six deaths but just over half of hospitalisations.
That leaves a lot of vulnerable at risk - and with the numbers in hospital still above the peak in the first wave, the NHS isn't yet out of the woods.
From Monday, the vaccination programme enters a new phase, with over-65s and the clinically vulnerable being invited to book a jab.
The JCVI defines clinically vulnerable people as those with conditions including chronic respiratory disease such as chronic obstructive pulmonary disease, cystic fibrosis, and severe asthma.
Some regions have already started vaccinating people aged 65 to 69, with NHS England having previously said that people in this age group could get a vaccine if GPs had supplies.
Earlier, Foreign Secretary Dominic Raab rejected calls from MPs in his party to put a date on when England's lockdown measures will be eased, saying the government will be "cautious".
On Saturday, the prime minister said he was "optimistic" he will be able to set out plans later this month for a "cautious" easing of England's lockdown, citing "huge progress" made with the vaccine rollout.
The UK is currently administering doses of two vaccines approved by the medicine regulator - the Pfizer-BioNTech jab and the one developed by Oxford University and AstraZeneca.
A third vaccine, made by US company Moderna, has been approved but supplies are not expected to be available until spring.
The UK is also lined up to receive at least three other vaccines if they are approved for use.
Its vaccination rate is the third highest in the world, behind only Israel and the UAE.
- LOOKING FOR SOMETHING TO WATCH?: From terrifying horror 'The Babadook' to multi-Oscar-winning 'Shakespeare in Love' - there's a film to suit your mood on BBC iPlayer
- THE THURSDAY MURDER CLUB: Escape the week with Richard Osman's bestselling crime novel...