Prime Minister Boris Johnson says all over-18s will be offered a Covid booster jab by the end of January.
The jabs will be offered in order of age groups, handed out in descending order in five-year bands.
Yesterday the JCVI recommended boosters should now be offered to everyone over 18.
Mr Johnson added it was "time for another Great British vaccination effort".
He told a Downing Street press conference: "Even if you've had your second jab over three months ago and you're now eligible please don't try and book until the NHS says it's your turn.
"We're going to be throwing everything at it to ensure everyone eligible is offered that booster in just over two months.
"All of our sites will increase their capacity and we'll stand up extra hospital hubs.
"There will be temporary vaccination centres popping up like Christmas trees"
He said he could understand people feeling frustrated after the emergence of the omicron variant of Covid but said it was "the wrong thing to feel" as "our position is immeasurably better than a year ago".
Mr Johnson added scientists were working to "crack the omicron code".
Health Secretary Sajid Javid said the booster programme would be "on steroids" with "hugely ambitious targets".
He said: "I have no doubt they (the NHS) will rise to the challenge as they have throughout this pandemic.
"This is a national mission and we all have a role to play."
He urged people to "step up, roll up our sleeves and get protected when the time comes."
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