More than 20 million adults in the UK have had both doses of a coronavirus vaccine.
Health Secretary Matt Hancock hailed the milestone, which he said means millions now “have the fullest possible protection from this virus”.
The Government target of offering a first jab to all adults by the end of July remains on track, the Department of Health said.
Across the UK a total of 56,677,012 vaccines have been administered between December 8 and May 15, including 36,573,354 people with their first dose (69.4%) and 20,103,658 with their second (38.2%).
Mr Hancock said: “We have more great news about the vaccination rollout and are making extraordinary strides as 20 million people now have the fullest possible protection from this virus – huge thanks to the team for hitting this milestone.
“The latest real-world data has once again demonstrated how effective the vaccine is at providing life-saving protection, with two doses of the Pfizer vaccine providing 97% protection against mortality.
“Receiving a second dose is vital to ensure you have the ultimate protection from this deadly virus – I encourage everyone to book their jab as soon as they are offered it.”
Vaccines Minister Nadhim Zahawi said: “It is inspiring to see the incredible public response to our call to arms to get the jab. We have one the highest vaccine uptake rates in the world, but our work is not done yet.
“It’s time to redouble our efforts on the second dose, so please come forward for the second jab as it could be a life-saving extra boost of protection.”
It was announced on Friday that second-dose appointments will be brought forward from 12 to eight weeks for people aged 50 and above.
NHS England has advised that no-one needs to contact the health service.
People due to get their second dose in the next 10 days, up to and including May 24, should attend their appointment as planned.
In England the vaccine rollout is currently open to anyone aged 38 and older.
A vaccination bus has been stationed in Bolton this weekend amid concerns around the spread of the variant first identified in India.
Mr Hancock has confirmed over-35s will be able to book their Covid-19 jabs from some point in the coming days.
He told the BBC: “This coming week we’re going to be opening up vaccination to the 35s-and-over across the country because this isn’t just about accelerating the vaccination programme in Bolton, it’s about going as fast as we possibly can nationwide.”