More than 20 million people in the UK have now been given their first dose of a coronavirus vaccine.
UK Health Secretary Matt Hancock says it's a "magnificent achievement for the country".
"I want to thank every single person who's come forward to get the jab," he said in a video posted to Twitter.
"Every jab in the arm is another life soon to be protected from this awful disease and means we are a step closer to returning to our normal lives."
It comes as nearly two million people aged 60 to 63 in England are being invited to book a coronavirus jab.
More than three in four people aged 65 to 70 took up the offer of a vaccination, the National Health Service said.
Prince William has urged Brits to keep on taking the COVID-19 vaccination so younger generations will feel it's important for them to have it.
William also warned against "rumours and misinformation" on social media about coronavirus jabs, as he and Kate talked by video.
His comments came after the Queen encouraged those hesitant about vaccination to "think about other people rather than themselves".
Meanwhile, British health authorities have identified the UK's first cases of the Manaus variant of coronavirus, a new strain that may spread more rapidly and may respond less well to existing vaccines.
Up to six cases of the concerning variant first detected in the Brazilian city have been identified in Britain, three in England and three in Scotland, it emerged on Sunday.
There are concerns that the existing vaccines may be less effective against the Manaus strain, although more research is needed.
The UK has suffered more than 122,000 coronavirus deaths and 4.1 million cases since the pandemic began.
Australian Associated Press