The prime minister has today announced that the booster rate will speed up and will open to everyone over the age of 18 who had their second jab at least two months ago.

The target for giving every adult in England a booster jab has been brought forward by a month over fears of a “tidal wave of Omicron” that could cause “very many deaths”.

Mr Johnson said Britain “must urgently reinforce our wall of vaccine protection” as he set a new deadline of jabbing everyone over 18 by the new year.

He said scientists had discovered that being fully vaccinated is “simply not enough” to prevent the spread of the coronavirus mutation and that, without a lightning speed mass booster campaign, the NHS could be overwhelmed.

The announcement comes as the UK Covid alert level was raised to Level 4, up from Level 3, following a rapid increase in the number of Omicron cases being recorded.

Speaking on Sunday, the prime minister said: “We’ve already seen hospitalisations doubling in a week in South Africa and we have patients with Omicron here in the UK right now.

“At this point our scientists cannot say that Omicron is less severe.

“And even if that proved to be true we already know it is so much more transmissible that a wave of Omicron through a population that was not boosted would risk a level of hospitalisation that could overwhelm our NHS and lead sadly to very many deaths.

“A fortnight ago I said we would offer every eligible adult a booster by the end of January.

“Today in light of this Omicron emergency I’m bringing that target forward by a whole month.

“Everyone eligible aged 18 and over in England will have the chance to get their booster before the New Year.”

Speeding up the jab rate will mean some NHS appointments will need to be postponed. Mr Johnson said there would be “even greater” cancellations if the Omicron wave was allowed to rise.

Every adult over 18 in England who has had a second dose of a vaccine at least three months ago will be able to have their booster from Monday, the Conservative Party leader added.