Boris Johnson has praised the Covid vaccination effort for placing the UK in an "incomparably better" position than this time last year.
In his New Year's message, the Prime Minister announced the country has met its target to offer all adults the chance to get a booster jab by the end of the year.
It's understood the measure is based on both the take-up of boosters and those eligible being contacted.
In a message, due to be shared on his social media on Friday, the PM said that seven in 10 eligible adults in England have now received their booster jabs - with an extra eight million vaccines delivered since the target was bought forward on December 12.
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He once again, however, urged caution for those celebrating the New Year.
"Whatever the challenges that fate continues to throw in our way and whatever the anxieties we may have about the weeks and months ahead, particularly about Omicron and the growing numbers in hospitals, we can say one thing with certainty, our position this December 31 is incomparably better than last year," he said.
"And as I speak tonight on New Year’s Eve, we’ve met our target, we’ve doubled the speed of the booster rollout, and it’s precisely because of that huge national effort that we can celebrate tonight at all," Mr Johnson said.
"Though I must of course urge everyone to be cautious and to take a test if you are going out and to remember the importance of ventilation," the PM said.
"Follow the rules if you are in Scotland or Wales or Northern Ireland."
England is alone in not having toughened rules on mixing after Christmas in a bid to limit the spread of Omicron - each of the other nations have brought in stricter regulations.
He will reference the UK’s economic growth, and say the response to the call to get vaccinated allowed the country to “maintain the most open economy and society of any major European economy”.
The PM's message continued: "And I want to speak directly to all those who have yet to get fully vaccinated.
"The people who think the disease can’t hurt them, look at the people going into hospital now, that could be you.
"Look at the intensive care units and the miserable, needless suffering of those who did not get their booster, that could be you.
"So, make it your New Year’s resolution, far easier than losing weight or keeping a diary, find a walk-in centre or make an online appointment."
Earlier in the week, the PM warned up to 90% of coronavirus patients in intensive care have not had a Covid-19 booster vaccine.
In his New Year's message, Sir Keir Starmer said the country needed leadership to ensure the sacrifices made during the pandemic were not in vain - promising a plan to offer security and prosperity to voters across the country.
The Labour leader will use 2022 to set out a plan to "build a new Britain" that "works for everyone," he pledged.
"I believe the best still lies ahead for Britain," Sir Keir said.
"That – if we make the right choices – together we can seize the future and make it work for every family in every part of Britain.
"That must be the true legacy of all the sacrifices and pain of the past two years of the pandemic."
The Labour leader will begin 2022 with his party ahead in a series of recent opinion polls, as Boris Johnson suffered a bruising December - his own MPs rebelling, a row over Downing Street parties, and the North Shropshire by-election loss.
For the Labour leader, the year would be spent "setting out, in detail, the ideas that I believe can build a new Britain – a Britain that works for everyone, in every part of the country and not just for those at the top".
As part of his plan to offer prosperity, Sir Keir said people needed to be equipped with the skills to be competitive in a global marketplace.
"All this demands a truly dynamic economy – ensuring that no city, no town, no village is left behind, as we buy, make and sell more in Britain," Sir Keir said.
"We will bring forward plans to show how this can work for every nation and region across our United Kingdom."
Liberal Democrat leader Sir Ed Davey used his message to say he hoped 2022 will be "the year we will finally beat Covid".
"Through all the ups and downs, the thing that has shone through the most for me is the remarkable courage, resilience and compassion of the British people," Sir Ed said.
"Everywhere I go, everyone I meet – you make me proud to be British, and optimistic for our future."
In Wales, Mark Drakeford urged people to "pull together" as he looked to "better and brighter times ahead," despite warning the country faces a difficult few weeks ahead.
In his new year message, the First Minister reflected on the past 12 months and thanked frontline workers and NHS staff for helping keep the country safe.
"Once again, our incredible frontline workers and NHS staff have gone far beyond the call of duty, working day in and day out to care for and protect us in our times of need. Thank you. Diolch o galon i chi gyd," Mr Drakeford said.
"As we look forward to 2022, we do so knowing the weeks ahead will be difficult. Omicron is here in Wales and is moving quickly through our communities.
"There will be better and brighter times ahead. Time to spend with friends and family – and time to make new memories. So please, let’s all pull together again as we head into the new year."
While Scotland's First Minister said "2021 had been dominated by the challenges of Covid".
Nicola Sturgeon thanked the efforts of frontline workers and the "sacrifices of people across the country" but stressed "we are facing a new challenge".
She appealed to Scots to "minimise New Year socialising as much as you can" adding: "This is not the Hogmanay we all wanted and hoped for".
"I believe we still can look ahead to 2022 with optimism," Ms Sturgeon adding, praising the booster vaccination programme as a way "back to greater normality".