Every adult in the UK could receive the required two doses of a coronavirus vaccine by September, or 'maybe sooner', health bosses said tonight.
Dr Clive Dix, chairman of the UK Vaccines Taskforce, said he was confident secure supply chains meant 'we can vaccinate as many people as the UK wants to vaccinate'.
He said it could be 'August time or September time all done, maybe sooner if we need to'.
The vaccine tsar's comments come as the Government today confirmed the number of people who have received their first dose of a vaccine is now approaching 15.6 million.
Figures show 546,165 have been vaccinated with a second dose.
Downing Street has previously confirmed the vaccine programme intends to reach all those aged 50 and over, as well as adults aged 16-65 in an at-risk group, by May.
Every person classed as being in the top four priority groups for a coronavirus jab has now been offered one, the Government has said.
Dr Dix, in an interview tonight with Sky News, said he was positive the flow of vaccine supply would remain on track over the next six months.
The target is to vaccinate the five top priority groups by April, then all remaining adults.
"We are confident within the vaccine taskforce now that the supply we're going to get will take to us to a position where we can vaccinate as many people as the UK wants to vaccinate," Dr Dix said.
"We're probably talking August time or September time all done, maybe sooner if we need to."
The Government today confirmed the deaths of 799 more people within 28 days of a positive coronavirus test.
That represents a drop of a quarter since the same time last week.
But new mutant variants of the virus continue to emerge, meaning speed is critical, especially for the most clinically vulnerable.
Tonight the Manchester Evening News reports thousands of people in Moston and Harpurhey are being invited for immediate tests after a case of a new Covid-19 variant was identified in the area.
It follows the same approach launched in Moss Side last week, after four cases of the same strain, E484K, were detected there.
Nearly 118,000 people now have died of Covid-19 in the UK.
However, daily deaths and cases are steadily falling amid the ongoing lockdown and nationwide vaccination programme. efforts.
Dr Dix, in the interview, revealed new vaccines could be approved in 'six to eight weeks' to tackle new variants - far quicker than it took for the first vaccines to be clinically approved.
And he said early data suggested the vaccines now in use were effective.
"You can never say for certain until you've got all of the data in, but all of the signs are incredibly encouraging," he said.
"It's looking like these vaccines are doing exactly what we expect - infection rates are going down, hospitalisations are going down and people are remaining - I wouldn't say virus-free, because we don't know that, but we know that they're not getting serious disease.
"That's what we were trying to do.
"The important thing is, if you think about the flu vaccine, the flu vaccine doesn't stop everybody getting flu.
"But it stops it being a severe disease and it stops people dying."
