More than 30 million people in the UK have now had a first COVID vaccine dose.
Government figures show 30,151,287 have had a first dose - around 57% of all UK adults - after 650,000 were administered on Saturday.
A total of 3,527,481 people have had two doses - 6% of adults.
Ministers remain confident that all over-50s will have been offered a first dose by 15 April. The government aims to offer all adults a jab by the end of July.
The 30 million threshold was passed as 3,862 new coronavirus cases and 19 deaths were reported on Sunday - down from 5,312 and 33 a week ago.
Prime Minister Boris Johnson tweeted that the new vaccination marker was "wonderful news" and urged people to "keep up the momentum" by getting a second dose when called.
Matt Hancock, the health secretary, said he was "absolutely thrilled".
"The vaccine is saving lives and is our route out of this pandemic. I want to say a massive thanks to the team. When you get the call - get the jab," he said.
Britain's first vaccine shot - and the first globally outside a clinical trial - was given to Margaret Keenan on 8 December.
The UK has planned to ensure everyone gets their second dose on time - in the 12-week timeframe, said a government minister on Sunday.
That means many in the older age groups will be fully vaccinated in the coming weeks.
"Yes, of course, we've been planning that all the way through," Culture Secretary Oliver Dowden told Sky News' Sophy Ridge.
"It's one of the most important considerations as we've rolled out the vaccine. In all of our planning, we have factored in getting that second dose of the vaccine."
The UK is also expecting its first batch of Moderna jabs next month, which could see the vaccine rollout expanded to those aged between 40 and 49.
"We examined the data from Moderna, which looks very promising," Professor Anthony Harnden, deputy chair of the Joint Committee on Vaccination and Immunisation (JCVI), told BBC Breakfast on Sunday.
"If we've caught up with all those over-50s we want to reach out to, it makes sense to go toward our next age group, which is the 40 to 49-year-old age group."
In all, the UK has ordered 17 million doses of the Moderna jab, 100 million doses of Oxford-AstraZeneca, and 40 million of BioNTech/Pfizer.
It has also ordered millions of doses of vaccines not yet approved by the UK's medicines regulator:
GlaxoSmithKline/Sanofi Pasteur (60 million doses)
Novavax (60 million doses)
Janssen (30 million doses)
Valneva (100 million doses)
CureVac (50 million doses)
The vaccine rollout's success is an important part of ensuring England's roadmap out of lockdown stays on track.
Boris Johnson has said there is so far nothing in the data that suggests it will be delayed.
On Monday, England's stay at home order ends, the rule of six returns outdoors, and organised outdoor sport can also resume.
People are still being encouraged to stay local however.
It comes a few weeks ahead of the next phase on 12 April, when outdoor hospitality, gyms and hairdressers can also get back to business.