Boris Johnson has said there is a "good chance" that no more restrictions will be introduced to tackle to spread of Omicron.
Addressing a Downing Street press conference, the PM said he would recommend to Cabinet on Wednesday that Plan B measures should stay in place, with no more additional restrictions at this point.
"If you are to ask me to guess, I would say we have — as I said earlier on — we have a good chance of getting through the Omicron wave without the need for further restrictions, and without the need certainly for a lockdown," said Johnson.
"I think the reason we’re in that position, unlike many other countries in the world, unlike many other countries in Europe, is that we just have such a high level now of booster protection.”
The prime minister warned that the weeks ahead are going to be “challenging”, accepting that some hospitals are already feeling "overwhelmed".
He said “some services will be disrupted by staff absences” as he pledged to “fortify” the NHS to withstand the pressures and protect supply chains.
Under the measures, he said 100,000 “critical workers” will get lateral flow tests on every working day starting on Monday.
He declined to give a definition of what would constitute the NHS being overwhelmed, but added that “different trusts and different places, at different moments, will feel at least temporarily overwhelmed”.
Johnson also pledged to give “plenty of time” before changing the definition of fully vaccinated to include a booster dose to obtain the COVID health certificate for entry to large venues.
While the prime minister has judged that further restrictions are currently not required in England, the NHS is facing significant pressure as it deals with the latest wave of COVID, coupled with high staff absences.
The latest NHS England figures show 14,210 patients with COVID-19 were in hospital on 3 January, up 48% from 9,546 a week before. Of these patients, 777 required mechanical ventilation.
The numbers are significantly lower than during the January wave of coronavirus, which saw more than 34,000 people in hospital with COVID at the peak, with a high of 3,736 people requiring mechanical ventilation.
Watch: Coronavirus in numbers – UK reports 218,724 new cases
Data continues to suggest that Omicron causes milder illness than Delta, though the vastly higher infectiousness of the new variant means the sheer scale of infections is placing the NHS under strain.
Speaking on Tuesday morning, the PM’s official spokesman said: “We’re not seeing that same jump in beds requiring ventilation, which is pleasing, and almost certainly a function of both the nature of Omicron and our successful booster programme.”
In London, which has so far been hit hardest by the Omicron surge, early signs suggest that infections may be plateauing.
Professor Neil Ferguson, of Imperial College London, told BBC Radio 4’s Today programme: “I would say that, with an epidemic which has been spreading so quickly and reaching such high numbers, it can’t sustain those numbers forever, so we would expect to see case numbers start to come down in the next week, maybe already coming down in London, but in other regions a week to three weeks."
However, Prof Ferguson said the Omicron variant had not had much time to infect pupils before schools shut for the Christmas break, and a rise in cases is now expected as children head back to the classroom.
Some 218,724 people were confirmed to have tested positive for COVID on Tuesday, another record daily figure.
However, the data had been affected by the bank holiday, with Tuesday’s data for Northern Ireland covering a four-day period, and for Wales covering a two-day period.
Watch: Daily politics briefing, 4 January