Half of all UK adults aged over 18 have now had a coronavirus jab, Health Secretary Matt Hancock says.
The government's target is to give all adults at least one dose of the vaccine by the end of July.
Mr Hancock confirmed the latest "success story" of the UK's vaccine progress this morning, after Britain's vaccine rollout figures passed 26million on Friday.
However the bright spot comes before a dip as the UK's bumper vaccine week will be followed by a lag in April when jab stocks are expected to be hit by delays.
Mr Hancock announced the milestone in a Twitter video, and wrote: "Yesterday we vaccinated more people than any day yet. I'm delighted to be able to say that we've now vaccinated HALF of all adults in the UK
"The vaccine is a national success story & our way out of this pandemic. When you get the call, get the jab."
The UK's vaccine drive has surged ahead of the European Union, after the government bet on a number of potential jab candidates early in the crisis.
The UK has rolled out the Pfizer/BioNTech and Oxford/AstraZeneca vaccines at pace, as Boris Johnson stakes his roadmap out of lockdown in part on the success of the vaccine rollout.
Jab immunity is hoped to replace restrictions on freedoms put in place to curb the virus, with a goal of ending the measures by July.
The Prime Minister had encouraged caution as he declared the July goal, saying the presence of worrying mutant variants could yet affect the UK's ambitions.
But today's achievement came as vaccine maker Moderna confirmed this week it remains on track to deliver supplies of its vaccine for the UK by next month.
Britain's vaccine blitz this past week saw it meet the halfway milestone by Saturday as vaccination teams got through the elderly and most vulnerable in the population at a speedy pace.
But the NHS has warned there could be delays of up to a month ahead for under-50s as the UK waits to restock its vaccine supplies.
Younger adults yearning for their jabs could face a lengthier pause than expected after the bumper vaccination week, due to a delay to a key shipment from March 29.
Also this week, British officials criticised EU countries that halted doses of the AstraZeneca vaccine amid blood clot fears.
The European medicines regulator declared the jab safe on Thursday, saying its benefits outweighed its risks.
But experts criticised the decision to halt the rollout for a safety review, accusing decision-makers of damaging public confidence in a jab declared safe by the UK's regulators and the World Health Organisation.
The European Union has struggled to keep pace with the UK's vaccine programme, with the disparity in approaches at times sparking bitter exchanges.
Mr Hancock posted the news of the vaccine this morning in a clip featuring the Union Jack flag and a portrait of the Queen.
The UK was plunged into bickering this week over Robert Jenrick's flag display.
BBC Breakfast co-host Naga Munchetty landed in hot water after liking a tweet referencing an interview on the show when co-host Charlie Stayt made a sarcastic comment about the size of the flag behind the Housing Secretary.
Her apology and the reaction to the saga prompted a war of words as some cringed over the display of nationalism and others insisted it symbolised British pride.
