Boris Johnson is locked in crisis talks today over whether to tighten Covid curbs - as a top Tory said there were no "guarantees" on whether new restrictions could come in before Christmas.
The Prime Minister has cleared his diary for emergency meetings with scientists and his top team as fears mount that new rules could be imposed in England this week.
Mr Johnson is said to be considering three different options, including limits to household mixing or even a return to lockdown.
The first proposal is to advise people to restrict indoor socialising - without making it mandatory under law.
Scottish First Minister Nicola Sturgeon has advised people to limit indoor mixing to three households over the festive period but it is not a legal requirement.
Option two is stricter. It would involve mandatory limits on household mixing, the return of social distancing and an 8pm curfew on pubs and restaurants.
The nuclear option is a return to full lockdown, according to The Telegraph.
The rapid spread of the Omicron variant has led to mounting alarm in Government, with 82,866 cases of Covid recorded on Sunday, up more than 50% in the past week.
Confirmed cases of the new strain have risen by more than 12,000 in the UK - and London's cases alone topped 10,000.
Scientists have called for tougher measures to prevent the NHS from being overwhelmed, as SAGE experts warned hospitalisations could rise to between 3,000 and 10,000 a day unless urgent action is taken.
The PM is also facing opposition from Tory MPs and even his own Cabinet over the imposition of new rules.
His authority has taken a battering in the last week after a disastrous by-election defeat, a mass Tory rebellion over imposition of vaccine passports, and the steady drip of damaging claims about rule-breaking parties in Government.
Conservative MPs are expected to receive a briefing from Chief Scientific Adviser Sir Patrick Vallance this afternoon.
Deputy Prime Minister Dominic Raab said today that he cannot make any "hard, fast guarantees" that more restrictions will not be needed ahead of Christmas Day.
He claimed that people were in a "better position to enjoy Christmas with loved ones" than last year - but refused to rule out new curbs.
Asked whether the government would impose further restrictions before Christmas, Mr Raab told Times Radio: "I just can't make hard and fast guarantees."
"In assessing the situation we rely very heavily on the real data coming through and it will take a little bit more time to assess this critical issue of the severity of Omicron."
He later told Sky News: "I do think of course, you have heard it from the Health Secretary over the weekend, I'd echo that, people will need to be careful and cautious.
"I do think that again, subject to the data, and it's always under review, we're in a better position to enjoy Christmas with loved ones this year."
Shadow chancellor, Rachel Reeves, told Good Morning Britain that the Government has got to "come out of hiding" and "put in place that pathway to getting on top of the virus and the infection".
She said: "If you look at Wales, for example, they have pre-announced a package of measures that will come in just after Christmas to get a control of this virus.
"The Sage minutes, the Government got those last Thursday. Four days on now, we haven't heard from the Prime Minister, we haven't heard from the Chancellor and they have access to much more data and advice than any of us.
"The Labour Party are ready to support the Government in whatever measures are needed to protect public health."
