The first UK death with the Omicron Covid variant was today confirmed by Boris Johnson.
The Prime Minister told broadcasters at least one patient has died with the strain. Mr Johnson did not say where the death took place or any other details of the patient.
It comes hours after the government confirmed there were 10 patients with the new Omicron variant in England's hospitals.
Speculation has been continuing about whether Omicron is less lethal than the Delta variant. But shock data has shown Omicron cases doubling every two to three days - suggesting even if it is less lethal, it could still overwhelm the NHS.
Last night the PM warned of a "tidal wave" and announced routine appointments would be scrapped in a bid to give a million booster jabs every day between today and New Year's Eve. No10 today said the aim is to give actual jabs by December 31 - not just make a booking.
Huge queues formed at vaccine walk-in centres this morning, the jab booking website crashed and lateral flow tests ran out until tomorrow. Over-30s can book from today, and over-18s can book from Wednesday or walk in today.
At the same time work-from-home guidance in England began today, and Mr Johnson faces a mass Tory revolt tomorrow over plans to force England's nightclub and event punters to show Covid passes from 6am on Wednesday.
Labour leader Keir Starmer will address the nation at 7pm tonight in response to the Prime Minister's address.
Today the government announced 750 troops have been "made available" to support the booster ramp-up, up from 400 announced previously.
700 personnel will administer jabs in England and Scotland, with another 50 helping logistical planning in England - including 41 planners in NHS regions.
That is despite Mr Johnson last night saying he would be "deploying 42 military planning teams" deployed "across every region" of England.
The PM's spokesman admitted there had been issues with the booking website and said capacity was being increased.
But Downing Street insisted 110,000 booster appointments had been booked by 9am on Monday through the national booking service.
The PM’s spokesman said the surge in demand showed the public understood the need for boosters, adding: "I expect the public will understand this is something we are doing at speed in light of a new variant…
"We are working to increase capacity and we will strain every sinew to do so."
Mr Johnson today refused three times to rule out introducing more restrictions before Christmas - as Scotland's Health Secretary said stricter rules are "inevitable".
Speaking during a visit to a vaccination clinic near Paddington, in west London, the Prime Minister said: "Omicron is producing hospitalisations and sadly at least one patient has been confirmed to have died with Omicron.
"So I think the idea that this is somehow a milder version of the virus, I think that's something we need to set on one side and just recognise the sheer pace at which it accelerates through the population.
"So the best thing we can do is all get our boosters."
Mr Johnson said Omicron now represents about 40% of coronavirus cases in London and "tomorrow it'll be the majority of the cases" in the capital.
He told broadcasters: "The risk is plainly there, we can see Omicron spiking now in London and some other parts of the country.
"Here in the capital it probably represents about 40% of the cases. By tomorrow it'll be the majority of the cases and it's increasing the whole time."
MPs will vote tomorrow on forcing nightclubs, large events and indoor venues with capacities over 500 to demand Covid passes from their punters as a condition of entry.
People will have to either show they have had two doses of a vaccine, or that they have taken a recent lateral flow test and it has come back negative. People will be able to show a text or email from the NHS testing service.
MPs will also vote tomorrow on face mask laws in theatres and cinemas that came in on Friday in England. More than 60 Tory MPs could rebel - but the measures will pass because Labour is backing them.
Mr Johnson said MPs thinking of rebelling against Plan B measures needed to recognise there was "no room for complacency" in dealing with Omicron.
He said: "I think that what everybody needs to recognise is a couple of things - that Omicron is a very serious risk to public health, and that it's spreading very fast, and I think there's no room for complacency."
The PM admitted "it became clear on Friday that two jabs were not enough" to hold off an Omicron wave, and urged adults to get their boosters - despite the website crashing.
Despite this, people will be able to show they've had just two doses to get into a crowded venue. Whether to up this to three doses is being kept under review.
It comes as Scotland's Health Secretary said stricter Covid restrictions are "inevitable" due to the spread of the Omicron variant north of the border.
Humza Yousaf said additional curbs were likely to be announce shortly as the country battles with the new strain.
First Minister Nicola Sturgeon is expected to make a Covid statement to the Scottish Parliament on Tuesday.
Boris Johnson refused three times to rule out further Covid restrictions being introduced in England before Christmas, admitting “there are still some important things we don’t know”.
The PM, who cancelled families’ Christmas plans on December 19 last year, the day after the No10 Christmas party, would not give a guarantee.
He said: "Throughout the pandemic I've been at great pains to stress to the public that we have to watch where the pandemic is going and we take whatever steps are necessary to protect public health.
"We think the steps that we are taking - so Plan B, combined with a hugely ambitious acceleration of the booster campaign, bringing it forward by a month so we offer a booster to every adult by the end of the year - we think that's the right approach."
Asked a third time to clarify he could not give a guarantee, he replied: “What I can tell you is we think that looking at the balance of the risks… the epidemiology… where we are with Omicron, everything we know - don’t forget, there are still some important things we don’t know about Omicron - we think this is the best approach.
“A combination of Plan B, which is some sensible steps to slow the spread of the virus to buy us some time to help to reduce the infections and of course the mortality rate.
“And then combine that with rapidly building up our booster defences.”
The PM was facing questions for the first time since the Sunday Mirror revealed he chaired a virtual quiz with two colleagues socialising by his side during last year’s ‘Tier’ lockdown rules.
Legal experts and Labour leader Sir Keir Starmer say Mr Johnson appeared to have personally broken Covid laws. At the time, indoor social gatherings in London between different households were banned by law.
Today Mr Johnson insisted he "certainly broke no rules" during the quiz.
But he admitted it will be looked at as part of an existing inquiry by Cabinet Secretary Simon Case, which is already looking at three other gatherings.
He said: “All that is being looked into. But if I may respectfully say to you... of course, all that must be properly gone into - you'll be hearing from the Cabinet Secretary about it all."
He said the Cabinet Secretary would report back "as soon as we reasonably can”.
Mr Johnson added: "But frankly, when I look at what we're trying to do now, the crucial thing is that people understand the challenge that is posed by Omicron. But also understand that this is a challenge that collectively we can meet.
"What I'm focused on, frankly, is the vaccine rollout."
