People aged 56 to 59 can now book their Covid-19 vaccine.
It comes after the rollout was extended to include those aged 60 to 63 on Monday and after eight in 10 people aged 65-69 took up the offer of a jab.
Almost 21.8 million adults in the UK have now had at least one dose of the coronavirus jab, 18 million of who are in England, meaning one-in-three adults there have been vaccinated.
ITV News Political Reporter Shehab Khan explains the government's vaccine rollout target
As of the end of Friday, March 5, the number of people in the UK to have been given a first dose of the jab is 21,796,278 - an increase of 437,463 compared to the previous day - while a total of 1,090,840 second doses have been administered - an increase of 56,772 compared to the previous day.
It means the equivalent of 2% of UK adults are now fully vaccinated against coronavirus, with almost one-third of the population having had at least one jab.
Who is getting vaccinated when?
The vaccine will be distributed to these 12 groups in the following order, according to the list drawn up by the JCVI.
In brackets is the estimated number of people in each group in the UK:
Phase one priority groups (to be offered first dose by mid-April)
1 - Residents in a care home for older adults and their carers (800,000 people)
2 - Those aged 80 and over and frontline health and social care workers (a total of 7.1 million people in this group: 3.3m over 80s, 2.4m healthcare workers, 1.4m social care workers)
3 - Those aged 75 and over (2.3 million)
4 - Those aged 70 and over and clinically extremely vulnerable individuals (4.4 million)
5 - Those aged 65 and over (2.9 million)
6 - All individuals aged 16 to 64 with underlying health conditions which put them at higher risk of serious disease and mortality (7.3 million)
7 - Those aged 60 and over (1.8 million)
8 - Those aged 55 years and over (2.4 million)
9 - Those aged 50 years of age and over (2.8 million)
Phase two (to be offered first dose by mid-July)
10 - All those aged 40-49 years
11 - All those aged 30-39 years
12 - All those aged 18-29 years
The government aims to have offered all adults in the top nine priority groups at least one dose of the coronavirus vaccine by mid-April, with all over-18s offered a jab by the end of July.
Dr Nikki Kanani, NHS England national medical director for primary care, said: "The NHS vaccine programme is committed to protecting the country against coronavirus and it is testament to our incredible staff that we can now move on to the next age group.
"We must not forget that our success in vaccinating more than 18 million people is down to careful planning and the hard work of those staff.
"The vaccines are both safe and effective, so if anybody who is eligible but hasn't been vaccinated yet, I'd urge them to go online or call 119 and get themselves booked in."
Health Secretary Matt Hancock said more than nine in 10 of those aged 65 and over and nearly nine in 10 people who are clinically extremely vulnerable have received a first dose.
He said: "It's an extraordinary feat and we remain on track to offer a first vaccine to all adults by July 31.
"We are now inviting people aged 56 to 59 to get their jabs and I urge everyone eligible to come forward as soon as possible."
NHS England added: "Vaccinations are now being administered at more than 1,600 sites across the country, including mosques, museums and rugby grounds, with the distribution of centres meaning 98% of the country lives within 10 miles of at least one vaccination service.
"People can use the national booking service to reserve a slot at a NHS vaccination centre or one of the pharmacy-led services across the country."
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