PM says "the scientists have done it" after UK becomes first country in world to approve Pfizer/BioNTech vaccine for widespread use
But he warns the tier system remains crucial and people must continue to follow the rules as it will take time to roll out the vaccine
England's deputy chief medical officer Jonathan Van-Tam says "people need to get on this train" and get the jab when it is offered to them
Regulator Dr June Raine says that "no corners have been cut" in approving the vaccine
Priority list of those who will get the vaccine first is published - care home residents at the top
Meanwhile, new three-tier system of restrictions has come into force in England, as four-week lockdown ends
WHO issues stricter guidance on mask-wearing indoors and outside
France to carry out random border checks to deter citizens from going abroad on ski holidays
Nearly 64m cases of coronavirus globally and more than 1.4m deaths, according to latest Johns Hopkins University figures
Jonathan Blake
BBC political correspondent
As expected the prime minister is striking a cautiously optimistic tone.
But the final line of his opening remarks is telling.
We can now be “sure and certain”, he says, that we will be able to reclaim our lives. It is a case of when, not if.
The second public question asks whether hospitality restrictions will remain in place over the Christmas period.
Johnson says he is "sorry to say" the guidance already set out in the tiering system will still be in place.
The PM adds it would be a "really fatal mistake now to respond to this good news by letting the virus run riot again".
We have now moved to questions from the public. The first is from Dillan, a student, asking about the plans for exams next summer.
Boris Johnson says they will be giving more details tomorrow about exams.
He says the government wants them to go ahead, but he says they will set out some ways they will help pupils do them given the “exceptional circumstances”.
Jonathan Blake
BBC political correspondent
Sir Simon Stevens has been notable by his absence in public throughout the pandemic, something which has surprised some given his position.
As the chief executive of NHS England he has overseen the health service through the unprecedented challenge presented by coronavirus.
But while he has not been a regular face at the Downing Street briefings, he clearly felt today's news of the vaccine was significant enough to appear in person and provide details of how the NHS would provide it.
Van Tam warns it will be "months, not weeks" for the rollout to take place, so appeals to people to stick by the restrictions and social distancing.
"Nobody wants lockdown," he says. "But if you want that dream to come true as quickly as it can come true then you have to take the vaccine when it is offered to you."
He concludes: "Stick to the guidance until we say it is safe to stop."
But the journey isn't over yet.
Van Tam says we need more vaccines than just the first one available.
And we need people to take it - with two doses needed for "full protection".
He adds: "Watching others take it and hoping this will then protect you isn't going to work necessarily as we don't know if it will prevent transmission".
And while Van Tam is hopeful, the rollout won't be instant.
Image source, PA MediaDeputy chief medical officer, Jonathan Van Tam, is next up, saying he was "quite emotional" when he heard the vaccine announcement this morning.
"What a momentous journey," he adds praising the Turkish scientists, US pharmacies and UK scientists who did the work.
"The train has now slowed down safely, it has stopped in the station and the doors have opened," he adds.
"Now we need people to get on this train."
But he appeals for "patience" and realism about the roll-out.
Sir Simon Stevens says delivering the vaccine will be “logistically complicated”.
He says it will have to be moved around the country in a “carefully controlled” way.
Next week, he says around 50 hospital hubs around England will start offering the vaccine to the first in line.
That will be followed by GP practices coming together in each area to operate local vaccination centres – growing to over 1,000 across England, who will invite patients to come for vaccines.
It will be a phased programme and he says the NHS will contact you if you are ready to be offered the vaccination. He says the optimism “needs to be tempered with realism”.
Image source, PA MediaNow it’s the turn of Sir Simon Stevens, chief executive of NHS England, at the Downing Street press conference.
He says today’s news brings “great optimism” but he says the vaccine announcement also brings questions.
Regarding who will be first in line, he says the first people to be offered the vaccine will be those at highest risk – over 80s, as well as people in care homes and frontline staff looking after them.
He says the rollout will be extended in the new year.
In terms of when it will be delivered, he says it will start in December but the bulk of doses for the at-risk population will be from January to April.
He also says we have to reserve the second dose for those people who get the first dose in December.
Johnson says the new restrictions that came into force in England today are necessary to keep the virus under control until the vaccine is rolled out.
But he says we are "no longer resting on the mere hope that we can return to normal next year but the sure and certain knowledge" we will.
The PM concludes his remarks by thanking all those who have taken part in trials, along with the scientists who made the breakthroughs.
The PM says the UK has bought 40 million doses of vaccines, and the rollout will begin next week.
Top of the list is the elderly in care homes, as well as health and social workers.
The rollout will be an "immense logistical challenge", due to factors such as the temperature it needs to be stored at.
But Johnson says it will be "some months before all the most vulnerable are protected" and we must not get "carried away with over-optimism".
"Our plan does rely on all of us continuing to make sacrifices for those we love," he adds.
Image source, PA MediaBoris Johnson begins the press conference by saying it has been almost a year since "humanity was tormented by Covid".
He says we have been waiting for the "searchlight of science to pick out our invisible enemy" and "now the scientists have done it".
The PM says the new vaccine meets the "strictest" health and safety requirements.
Boris Johnson has taken to the lectern to begin today’s government press conference.
Stay with us as we bring you all the news and analysis.
Jonathan Blake
BBC political correspondent
The prime minister summed up his thoughts in the House of Commons earlier, telling MPs: "This is very, very good news".
The approval of a vaccine for use in the UK is undoubtedly a triumph the government will want to make the most of.
But with the opportunity that a viable vaccine provides comes the challenge of successfully distributing it.
The good news will barely be sinking in before the government faces questions about who gets the vaccine, when and how.
Expect Boris Johnson to manage expectations, having already warned people not get their hopes up about a rapid roll-out, and that restrictions will be needed for some time yet.
Just five minutes to go until we hear from the prime minister.
The press conference comes as England enters it new tougher tier system. But what does that mean for you where you live?
Watch our video below – or if you are in Scotland, Wales or Northern Ireland, read our guide on your local restrictions here.
Covid-19: What is the new three tier system after lockdown?
Hugh Pym
BBC News Health Editor
The pace has been breath-taking.
From an unknown virus at the start of the year to a vaccine approved by the regulator and ready to use in early December is an unprecedented timescale.
At the Downing Street briefing, the MHRA’s chief executive said it was like climbing Everest, with preparations starting in June and a team working “night and day” assessing early data and reaching “base camp” by early November when Pfizer/BioNTech published the trial results.
At the same time, the MHRA was adamant that the process had been robust with safety considerations paramount.
A rapid emergency approval process was used by the UK regulator.
The European Medicines Agency is taking longer to reach a view and there has been some sniping from European politicians arguing their processes are more reliable and authoritative.
But the MHRA is an internationally respected, independent watchdog and, for now, those about to receive to the first jabs will rely on its ruling.
We will be hearing from Boris Johnson shortly, along with the chief executive of NHS England, Simon Stevens, and deputy chief medical officer, Jonathan Van Tam.
But while we wait, watch this moment from the Commons, where a tearful Health Secretary Matt Hancock shares his story of losing a loved one to Covid.
Coronavirus: Health Secretary Matt Hancock reveals his step-grandfather died of the virus
Image source, EPAPfizer plant in Michigan used for vaccine cold storage
Americans are wondering when they'll get a vaccine now that the Pfizer/BioNTech jab has been approved for use in the UK. Pfizer is a US company - its partner in the vaccine, BioNTech, from Germany.
It'll be down to the US regulator, the Food and Drug Administration (FDA), to decide at a meeting next week.
Another vaccine, manufactured by Moderna, will be considered by the FDA a week later.
Vice-President Mike Pence said on Monday that Americans could start receiving the vaccine "as soon as the week of December 14".
US vaccine timetable:
8 Dec - White House summit with vaccine firms
10 Dec - FDA could approve Pfizer
14 Dec - rollout of Pfizer vaccine could begin this week
17 Dec - FDA could approve Moderna
The US has recorded a total of 13.6 million cases and some 270,000 deaths, according to Johns Hopkins University.
Image source, PA MediaWe should be hearing from UK Prime Minister Boris Johnson in the next 30 minutes to update us on the latest coronavirus news, but let’s take a look at the latest from the country first: