Boris Johnson has pledged that every eligible adult will be offered a booster by the end of the January.
The government is dramatically ramping up its vaccination programme and reintroducing covid measures over concerns about the omicron variant.
Johnson confirmed the government was deploying the army to help the NHS as he vowed to get boosters in arms.
All adults will be offered a booster three months after their second dose, working down the age cohorts five years at a time.
But the prime minister also tried to strike a positive tone today, saying temporary vaccination centres will be “popping up like Christmas trees”.
It comes after a split emerged between the government and a scientific adviser over socialising.
“The target that we’ve set ourselves is to offer a booster to everyone eligible by the end of January,” Johnson told a Downing Street press conference.
“As with the first jabs, we will be working through people by age group going down in five-year bands, because it is vital that the older and the more clinically vulnerable get that added protection first.
“So, even if you have had your second jab over three months ago and you are now eligible, please don’t try and book until the NHS says it is your turn.”
Booster jabs have been extended to 18 to 39-year-olds with the waiting time between second and third doses halved to three months.
However, the PM urged people to wait to be contacted by the health service before booking their booster, adding: “Even if you have had your second jab over three months ago and you are now eligible, please don’t try and book until the NHS says it is your turn.”
NHS England chief executive Amanda Pritchard said staff were working at “breakneck speed” to expand the vaccine programme, which was already at its “most complex phase”.
A total of 22 cases of the new omicron variant have so far been confirmed in the UK.
This article originally appeared on HuffPost UK and has been updated.