Vaccination centres are set to 'pop up like Christmas trees' as the government attempts to bolster the country against the Omicron variant of Covid-19.

Speaking at a press conference this afternoon, Prime Minister Boris Johnson also announced army personnel would be brought in to help support the drive to give millions of people aged over 18 a booster jab before the end of January.

He said boosters would be offered in five year age group bands, with jabs offered at pharmacy sites and temporary vaccination centres.

And while he admitted many would feel a "sense of exhaustion," he added: "that's the wrong thing to feel as our position today is immeasurably better than it was a year ago.

"We are taking precautionary measures while our scientist crack the Omicron code.

"Whenever your turn comes, get your booster and ask your friends and family to do the same. It's time for another great British vaccination effort.

"We've done it before and we'll do it again. Let's not give this virus a second chance."

Health secretary Sajid Javid said there had been 13 confirmed cases of the Omicron variant in England and nine in Scotland, with numbers expected to rise in the next few days.

He said it was not yet known to what extent the current vaccines offered protection against Omicron, but added: "although it's possible they are less effective, it's unlikely they will have no effect."

He said the NHS had already secured "hundreds of thousands of doses of antivirals", but that the vaccination effort remained key.

"This is a national mission and we all have a role to play," he added.

"If we want to give ourselves the best chance of a Christmas with our loved ones, the best thing we can all do is step up, roll up our sleeves, and get protected."