Health Secretary Matt Hancock celebrated the news on Twitter on Sunday, sharing a video and message to mark the milestone.
Mr Hancock, who gave an update on the nation’s vaccine roll-out programme at a Downing Street briefing on Friday, spoke of his delight on social media, adding: “A magnificent achievement for the country.”
He continued: “The vaccine is our route out. When you get the call, get the jab.”
The Health Secretary previously praised the North East for “working wonders” with the vaccine roll-out in the region at Friday’s briefing, thanking both volunteers and NHS staff for playing their part in giving out the life-saving jabs across the region.
He told Friday’s press conference: “The North East has done a brilliant job on vaccinating. It came out of the blocks really fast and has worked absolute wonders. “
Vaccines minister Nadhim Zahawi also recognised the national vaccination programme’s milestone on social media on Sunday.
He tweeted: “Bingo! One score over 20,000,000 people have had the vaccination (first dose).
"What an achievement for February 2021. What a team! Proud to be with you on this journey.”
The first injections of the UK’s Covid-19 vaccine roll-out were given on December 8.
At the start of this year as Lockdown 3 was imposed, the Government set a target for all of those in priority groups one to four, as decided by the joint Committee on Vaccination and Immunisation (JCVI), to have received their first dose of Covid vaccine by February 15.
This group included all of those aged 70 and over, residents in care homes for older adults and their carers, frontline health and social care workers and the clinically extremely vulnerable.
Starting on Monday, March 1 almost two million 60 to 63-year-olds are expected to receive invites to book in for their first Covid-19 vaccine dose.
They have been sent after more than three in four people aged between 65 to 70 took up the offer of a vaccination.
It is the aim that all of those aged 50 and over will have been invited to receive a first dose of vaccine by April 15.