People are being ordered to wear masks in shops and on public transport again in response to the arrival of the Omicron variant in England.
Boris Johnson also announced that contacts of Omicron cases must isolate for 10 days, until the danger from its mutations are known – and the return of day 2 PCR tests for all international travellers, even the fully vaccinated.
Calling the measures “temporary and precautionary”, he told a press conference: “We will review them in 3 weeks.”
Asked why he was not imposing the government’s full ‘plan B’ – also including vaccine passports and working from home – Mr Johnson insisted the UK is still in a “much, much stronger position” than earlier in the pandemic.
Omicron could be tackled by efforts to “slow the seeding with the tough measures we are taking at the border” – while more booster jabs are delivered, to beef up protection.
But he did not rule out further festive restrictions, saying only: “I’m absolutely confident that this Christmas will be considerably better than last Christmas. That will do for the time being.”
Speaking after the first two Omicron cases were found – in Essex and Nottingham – Mr Johnson also revealed moves to expand booster jabs to under-40s and cut the six-week gap between a second jab and a booster.
The Joint Committee on Vaccination and Immunisation (JCVI) has been asked to consider the changes – in a clear sign that ministers want them to happen – although the prime minister called it “an independent body”.
“Clearly we hope we will get some answers for everybody as soon as possible,” he told the press conference in Downing Street.
Mr Johnson also rejected criticism that the spread of the new variant in southern Africa showed the folly of rich nations failing to deliver vaccines to poorer nations.
He claimed the problem in such countries has “not been supply, but hesitancy and lack of take-up”, arguing the UK has been “leading” the world in sharing jabs.
Chris Whitty, the chief medical officer, warned of “a reasonable chance of some type of vaccine escape” from the Omicron variant, but said jabs should still offer protection against serious disease.