A senior Whitehall source revealed that "bubbles" could make a return – although the Prime Minister is believed to be opposed to his policy.
“There’s no doubt ministers and officials have been spooked," a senior Government official told i News.
"Not only by the rapid escalation of Omicron case, which was expected but also the testing supply issues we’ve seen as a result of the huge increase in the booster rollout programme to all over adults.
“But the biggest issue is that even if everyone that wants a booster can get one before the end of this month, they will still not be protected against Omicron before Christmas."
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Pubs, shops and restaurants could be forced to shut in January due to Omicron
Other restrictions could include social distancing and wearing masks inside pubs and restaurants.
"For many in Whitehall, and some ministers, further restrictions are the only way of stopping millions of Omicron within a couple of weeks.
"Therefore, some form of restrictions over Christmas are becoming more likely every day.”
It comes after MPs were allegedly warned to be "on standby" to vote on new restrictions during Christmas week
Read our Omicron live blog for the latest updates
Plan C may be enacted before Christmas as MPs have been told to prepare for a Parliament recall on December 21 if the Covid situation spirals, it's been reported.
This means indoor mask-wearing and table service in pubs and bars may be back before the festive season.
And according to sources, a Plan D is already being considered – which would force punters to dine outdoors again.
This is despite the fact that boosters offer up to 75 per cent protection from mild infection from Omicron, and the undoubted hit the service industry economy would take.
Omicron is coming at us like an express train
A Health Department source told the Mirror: “If you follow the science, we should really be doing Plan C now. The PM is gambling with the NHS to save his leadership.
“But we all know the PM can’t let anything hit Christmas. That really did him damage last time round. To do it again would be killer.”
Boris is allegedly hoping he can postpone any new restrictions needed until New Year’s Day at the earliest.
Professor Stephen Reicher of St Andrews University added: “Omicron is coming at us like an express train. We must slow it down to buy time otherwise we will be in a crisis at Christmas.”
But data shows that Covid vaccines do protect you from Omicron – and getting your booster before the festive season will protect you and your loved ones.
The Sun's Jabs Army helped administer millions of jabs this year – and now we are calling Brits to get their boosters.
Meanwhile, Sajid Javid has been told to trigger Plan C restrictions within a WEEK by gloomy health officials, it's been reported.
The Health Secretary was allegedly told by doom-mongers at the UK Health and Security Agency that Omicron risks overwhelming the NHS as 5,000 Brits could be admitted to hospital a day.
Mr Javid was allegedly told that “stringent national measures” need to be imposed by 18 December to avoid surpassing last year's winter peak.
In documents seen by the Guardian, the advice said that the tough action is "needed in December."
The "official and sensitive" warning to the Health Secretary said: "The key point is that under a range of plausible scenarios, stringent action is needed on or before 18 December 2021 if doubling times stay at 2.5 days.
"Even if doubling times rise to around 5 days, stringent action is likely still needed in December.”
It adds: “The rapid spread of Omicron means that action to limit pressures on the health system might have to come earlier than intuition suggests.”
This comes as Michael Gove has hinted that Plan C restrictions are on the cards as he warned that the spread of Omicron was "deeply concerning."
The gloomy minister warned Britain faces an onslaught of mutant Covid cases — as he opened the door to further restrictions under Plan C.
The Levelling up and Communities minister insisted: “We need to keep everything under review.”
He said: “We recognise the importance of balancing people’s abilities to get on with their lives, with the need to protect them against this virus. But action is absolutely required.
“As new data comes in we will consider what action we do require to take in the face of that data.”
Gove appeared to open the door to new Covid restrictions while admitting the UK faces a "deeply concerning situation" because of Omicron.
However – a third jab can combat Omicron and save us from more lockdown pain, says a morale-boosting study.
Any two doses plus a Pfizer booster give up to 75 per cent protection, experts say.
Three shots also defend better against severe disease or death — but two doses will soon fail to prevent even a third of cases.