Thanks for tuning into our coverage today.

Here are the latest headlines from the UK and around the world:

• More of the east and south east of England will enter tier four on Boxing Day, Health Secretary Matt Hancock has announced. Areas moving up to tier four include Sussex, Oxfordshire, Suffolk, Norfolk and Cambridgeshire
• Two cases of another “more transmissible” variant of coronavirus from South Africa has been detected in the UK
• France has eased its travel ban on the UK, with French citizens, British nationals living in France and hauliers allowed in as long as they test negative for the virus
• Members of New York City’s Sheriff’s office will conduct home visits to ensure people from the UK are quarantining
• Hundreds of immigrants in France working on the coronavirus front line have been recognised with fast-track citizenship
• Taiwan’s president has called for calm after the first local transmission was reported since April
• The US state of California has surpassed two million cases. Half a million of those were over the past two weeks

Today's live page was brought to you by Sarah Fowler, Victoria Lindrea, Becky Morton, Ritu Prasad, Gavin Stamp, Lauren Turner, Kate Whannel, Sophie Williams and Cherry Wilson.

We'll be back with more tomorrow.

For many, Christmas this year is going to be very unusual.

Gwen Jones, a mental health blogger from Cardiff, shares her tips for coping with the festive period.

"Be an observer of your thoughts, not a sufferer," she says.

She compares our minds with a railway station and our thoughts to passing trains, and urges people to make use of any support they have.

Image source, Getty Images

In North America, vaccine rollouts are moving forward.

Canada's health agency authorised the Moderna vaccine on Wednesday, saying in a release that "after a thorough, independent review of the evidence, it has determined that the Moderna vaccine meets the department’s stringent safety, efficacy and quality requirements".

Prime Minister Justin Trudeau has said Canada will have 168,000 doses by the end of the month.

In the US, where the Covid case count has topped 18 million, the federal government has agreed to a $1.95bn deal with Pfizer for 100m doses. At least 70m will be delivered by 30 June.

The US Centers for Disease Control reports that 4.6m doses have been delivered as of Monday, and more than 614,117 have been administered.

BBC News Analysis

Several counties in southern England will be put under tier four restrictions from Boxing Day.

Other areas were also moved into a higher tier as the government tries to contain the spread of the new variant of Covid-19.

All parts of England have been placed in a tier depending on factors such as the speed at which the virus is spreading or the strain on hospitals – four being the highest.

Restrictions in these areas include:

• Residents should stay at home, unless they have a "reasonable excuse" such as work or education
• All non-essential shops must close
• Hairdressers and nail bars must close

The whole of Wales has entered another lockdown. Mainland Scotland and Northern Ireland start new lockdowns on Boxing Day.

Read more here.

James Gallagher
Health and science correspondent, BBC News

Anyone singing In the Bleak Midwinter may want to write another verse.

Cases, numbers in hospital and deaths are all going up.

It’s likely the NHS will soon be dealing with more Covid patients than at the peak in April.

The new variants are causing concern – especially as the one detected first in the UK continued to spread even during the November lockdown.

Vaccines will be the solution, but they take time to roll out and until then it is going to be rough.

The only other tool we have to stop the virus spreading is reducing our contacts with other people.

That’s why millions more of us are moving up the tiers on Boxing Day.

The hope is that the night is darkest before the dawn and that come Spring, the virus’s grip on our lives will start to ease.

Image source, Reuters

As we mentioned earlier, ministers in Ireland are self-isolating and awaiting test results after a minister tested positive.

Charlie McConalogue displayed no symptoms but is self-isolating, his spokesman told the Irish Times.

He received his test result several hours after attending a cabinet meeting.

The agriculture minister had been in Brussels on government business over the last few days and was tested on his return, according to broadcaster RTÉ.

Read more here

Image source, Reuters

The first trucks have started leaving a temporary lorry park in Kent after France reopened its border with the UK.

It follows clashes with between frustrated hauliers and police, as drivers have become increasingly impatient to get home for Christmas.

France has lifted its ban on some UK arrivals, but only if they can show proof of a negative Covid test taken less than 72 hours before departure.

"We are very tired. We're staying in cars, we don't have a lot of food, no money," one lorry driver told the BBC.

"We just want to do the test and just go straight home," said another.

A huge backlog of traffic remains. It all adds to the pressure on the authorities to get as many tests done as quickly as possible.

Read more.

Image source, Reuters

Members of New York City’s Sheriff’s office will conduct home visits to ensure people from the UK are quarantining, Mayor Bill de Blasio said.

International visitors to the city will be handed an order to quarantine and could face a $1,000 (£740) a day fine if found not complying with the rules.

“We cannot take chances with anyone who travels, particularly folks traveling in from the U.K.,” de Blasio said.

New York was the epicentre of the outbreak in the US earlier this year.

The US state of New York has recorded 36,724 deaths since the outbreak began.

Teams of volunteers have delivered hundreds of meals to lorry drivers stranded in Kent.

Members of Maidenhead's KhalsaAid travelled 80 miles (130km) to take food to drivers hit by delays at the border.

On Tuesday, some of the Sikh charity's LangarAid members travelled almost double the distance, from Coventry, to bring water and food.

KhalsaAid founder Ravi Singh said: "It's horrible for [the drivers], there's nothing here - no food, no shops - it's like a prison for them.

"We can't sit back and do nothing."

Read more.

The health secretary has described the new variant of coronavirus which came to light in South Africa as " highly concerning".

Matt Hancock said the variant was "more transmissible and appears to have mutated further than the new variant that has been discovered in the UK".

In consequence, he said the government was quarantining the two cases found in the UK, as well as their close contacts.

The UK government is also placing "immediate restrictions" on travel from South Africa.

Mr Hancock said anyone who had been in South Africa in the past fortnight, or who had had contact with someone who had been in South Africa in the last two weeks, "must quarantine immediately".

Image source, Getty Images

Hundreds of immigrants in France working on the coronavirus front line have been recognised with fast-track citizenship.

The interior ministry invited residents helping with efforts against Covid-19 to apply for accelerated naturalisation.

More than 700 people, including healthcare professionals, cleaners and shop workers, have already been granted citizenship or are in the final stages of receiving it.

Read more here

Philippa Roxby
Health reporter, BBC News

Just as we’ve got used to the idea of one worrying variant of this coronavirus, another one comes along.

The newest one, which has been brought from South Africa in recent weeks and infected two people in the UK, is “highly concerning”, says Health Secretary Matt Hancock.

It comes hot on the heels of the discovery of another variant in Kent causing sharply rising cases in the south and east of England, which will mean strict tier four restrictions being introduced in more areas of England on Boxing Day.

These are two different variants, but they have some similarities and share a mutation.

Crucially they are both concerning, leading to large increases in cases in South African and the UK.

UK scientists are skilled at genomic sequencing - the technique used to track mutations of the virus. That’s the main reason these variants have been found quickly and acted upon, but just because other countries haven’t detected them yet doesn’t mean they aren’t present.

The faster they can be found, the more quickly they can be squashed. With hospital admissions rising to near levels of the spring peak and deaths increasing daily, ministers have no choice but to act quickly.

Cutting social contact between people, tighter rules on travel and rapid testing – which is being rolled out to workers in care homes and is planned in schools and many local authorities – are the tools they are using to fight the virus on all fronts.

Image source, Getty Images

In the last two weeks, California has seen half a million new coronavirus cases.

On Tuesday, America's most populous state hit two million Covid-19 cases and more than 23,000 deaths, according to Johns Hopkins University data.

Officials now predict hospital admissions could reach 100,000 in January if the spread continues.

The spike has left the state's health system overwhelmed. A number of intensive care facilities have been operating at over-maximum capacity, with less than 2% bed availability statewide. In Southern California, there is 0% ICU availability, local media report.

The state is also seeing a shortage of medical staff - and is now turning outside the US, to places like Australia and Taiwan, to seek temporary medical workers, the AP reports.

Health experts have continued to urge residents to practice social distancing during the rest of the holiday season, emphasising that hospitals may not be able to handle any further strain.

The number of daily positive cases in the UK has hit another record high, with 39,237 , externalpositive cases reported in the past 24 hours.

However, cases were thought to be higher in the UK during the spring peak when testing was much more limited.

Government data shows a further 744 people have died within 28 days of a positive test. The total death toll now stands at 69,051.

Health Secretary Matt Hancock has urged the British public "not to give up now".

"We know what we can control this virus; we know that we can get through this together," he said, after announcing new tier restrictions to be imposed on large swathes of England from Boxing Day.

"I believe that everybody will do what is needed to keep themselves and others safe, especially this Christmas," he said.

"And I know, from the bottom of my heart, that there are brighter skies ahead."

Today's Downing Street briefing has now come to an end.

Health Secretary Matt Hancock acknowledged that 2020 had been "a hard year" and despite all our efforts, the new variant of Covid-19 made further action "difficult but necessary".

Here's what we learned at the press conference:

• Sussex, Oxfordshire, Suffolk, Norfolk and Cambridgeshire will move into tier four - meaning they will be under England's toughest restrictions - from 00:01 GMT on Boxing Day
• The parts of Essex not currently in tier four, along with Waverley in Surrey, and Hampshire - including Portsmouth and Southampton but not the New Forest - will also be escalated to tier four
• Bristol, Gloucestershire, Somerset (including North Somerset), Swindon, the Isle of Wight, the New Forest and Northamptonshire, as well as Cheshire and Warrington, will move to tier three
• Cornwall and Herefordshire, which "have seen sharply rising rates", will enter tier two restrictions
• Covid cases have risen by 57% over the past week and hospital admissions are at 1,909 a day - the highest figure since mid-April
• Two cases of another new variant of coronavirus have come to light in the UK. Both patients had contacts who travelled from South Africa; they are currently in quarantine. New restrictions will be imposed on travellers from South Africa to the UK - and their contacts
• Vaccinations have begun for residents in care homes. In addition, care home staff will receive two rapid tests a week alongside their weekly PCR tests
• The Oxford-AstraZeneca vaccine has submitted its full data package to the MHRA for approval
• Mr Hancock said everyone will be vaccinated "as fast as we possibly can"

The last question comes from Arj Singh from HuffPost. He asks if, given the highly-transmissible new variant, the government is guilty of overpromising by suggesting the UK can return to normality by Easter.

Hancock replies that he is "highly confident we will get things back to normal before 2022" adding that the speed of the vaccine roll-out is accelerating.

And that is the final question. Hancock wishes everyone a happy Christmas before leaving the lectern.

Image source, Reuters

Sam Lister from the Daily Express asks how many people will be vaccinated by Easter.

Mr Hancock says he would love "to have a stab at the answer" but it depends hugely on the speed of production on the array of different vaccines that the UK has purchased.

He says he does not want to put pressure on regulators in terms of approving the Astra-Zeneca Oxford vaccine, knowing that they will undertake their work as thoroughly as possible.

He says the roll-out of the vaccine will be a "big task" for the NHS.

"The true answer will be as fast as we possibly can."

Image source, Reuters

Jane Merrick of the i asks why the whole country isn't going into lockdown. She also asks if, given evidence of increased infections among the under-15s, there is a case for mass testing in primary schools and a staggered return for primary schools as well as secondaries.

Hancock says the new variant is highly concentrated and the new tier rules are aimed at keeping the variant in the South East.

Dr Hopkins says "we have no evidence this virus is more transmissible in children yet".

"We will constantly take decisions with the experts in education over what is best for the children, along with controlling the virus," she adds.

Dr Harries says: "We shouldn't jump to the conclusion that just because every child is in school that it is a significant place for transmission."

Jessica Parker
BBC political correspondent

Will all of England end up in tier four? The health secretary says he wants action to be "proportionate" and that the current tiers system is working.

So that suggests more of a hopefully not, rather than never.

Wales has brought forward a lockdown. Northern Ireland will enter one on Boxing Day. At the same time, mainland Scotland will go into the tightest level of restrictions.

Ministers in England are still trying to keep a more local approach but, on future national measures, they’re certainly not ruling anything out.