The NHS coronavirus vaccine booking system has opened to healthy people aged 42 and over.
The national booking system has been extended for the second time in two days to allow more healthy adults in their 40s to book their jab.
People in England who are aged 42 and over, or those who will turn 42 before July 1, can now arrange their vaccine appointment through the national booking website.
The system only opened to those aged 44 and over on Monday.
There had been supply constraints throughout April, with second vaccines for those at highest risk of Covid-19 being prioritised with the supply that was available.
But even amid supply issues, the NHS was able to extend the rollout of the vaccine programme to its second phase, healthy adults under the age of 50.
The first of this group to be offered the jab was those age 45-49.
Within a week of the booking system opening, two thirds of this group had received their first vaccine.
It comes after the Prime Minister warned the UK would probably be hit with another wave of Covid-19.
But Boris Johnson said that coronavirus jabs would provide “pretty robust fortifications” should there be another spike in infections going forward, as he hailed the UK’s vaccination programme.
During a visit to Wrexham on Monday, he urged the public to take up the vaccine when offered it.
It comes as the Prime Minister denied saying he was prepared to let “bodies pile high” rather than order another lockdown, amid a bitter briefing war that has hit Downing Street.
On Monday a new campaign, called “every vaccination gives us hope”, was launched and includes a TV advert which will showcase the health workers and volunteers involved in the vaccination rollout across the UK.
The campaign will predominantly be aimed at people under the age of 50 who will be offered their first dose, as well as the over-50s who are booked in for their second dose, to encourage vaccine uptake.
Government data up to April 25 shows that of the 46,650,008 jabs have been given in the UK so far, with 12,897,123 second doses.
As well as the clinically vulnerable, healthy adults aged 35 and over in Northern Ireland have been invited to book their vaccine appointment.
In Scotland, preparations are ongoing to extend the vaccine rollout to healthy adults in their 40s.
People aged 30 and over are being called for their appointments across Wales.
Meanwhile medical supplies from the UK have arrived in India, which is facing a significant wave of infections, with some healthcare facilities in the country buckling under the strain.
The first of nine plane-loads of life-saving kit, including ventilators and oxygen concentrators, arrived in New Delhi early on Tuesday.
The move follows discussions with India’s government following a devastating surge in Covid-19 cases which has overwhelmed the country’s health services.
Further consignments are due to be dispatched later this week.