Image source, Reuters

In response to a question from Sky's Rob Powell, the health secretary reiterates that the old system of three tiers was sufficient to keep the old variant of Covid under check - but things have now changed.

Asked how the success of tier four will be measured, Matt Hancock says a lot will "depend on how people behave" in sticking by the rules and minimising social interactions - something the vast majority of people have done up to now, he adds.

Mr Hancock urges people to "stick at it and not give in to temptation" over Christmas and the New Year.

"This is a partnership. There is something that every single person should do," he says. "It is on us all."

Dr Harries says it is not inevitable the sharp rise in cases will continue if people adhere to the rules.

Image source, Getty Images

Daniel Hewitt from ITV asks why the government is delaying putting the whole country into tier four.

He also asks if there is any evidence to suggest the vaccine wouldn't work against the new Covid variant and whether the government will publish data on how many people have received their first dose of the Pfizer vaccine.

Hancock says the government will publish vaccine data tomorrow.

On moving areas into tier four, he says the government wants to be proportionate.

Dr Hopkins says there is no evidence that the vaccine will not work with the new variant.

We're now moving onto questions from the media, the first of which is from the BBC's Leila Nathoo.

She asks why tier four restrictions were not being extended to more of England and implemented immediately, given its spread, and asked if the government was "wasting valuable time".

Mr Hancock said ministers had acted incredibly quickly to bring in tier four and this was now being broadened.

He says there are areas where cases are falling and the tier system is designed to respond proportionately.

He stresses the importance of personal responsibility by the public over Christmas and the new year period.

On the new South African variant, Dr Hopkins says the authorities are learning about its properties all the time but the initial evidence is that it is a new more transmissible mutation.

She says it will be kept under genomic surveillance and she is confident the new tiering measures will keep it in check.

Dr Harries adds that further new variants are not a surprise.

Image source, PA Media

We now come to questions from the public. Tim, who is stuck in Germany until next year due to travel restrictions, asks what the government is doing to help.

Hancock says the government is "doing everything it can" including working with international colleagues to get British citizens home.

The second questioner asks about schools returning in the new year and also asks if the health secretary is considering rolling out the vaccine for vulnerable teachers.

Hancock says the government's new plan is designed to keep students and teachers safe.

On the vaccine, Dr Harries says the data doesn't suggest that teachers themselves are at risk. She acknowledges that teachers who are clinically vulnerable will be anxious - and says they will be included in "group six", meaning they can get the vaccine earlier than others.

While the number of cases attributable to the old variant is holding steady or tailing off in some areas, Dr Harries says there has been a very sharp rise in cases of the new variant.

This is translating into rising pressures on hospitals, she says.

The number of hospital beds currently occupied by Covid patients across England is nearing April’s peak of about 21,000, Dr Harries says, including in London.

Image source, COBR

Jessica Parker
BBC political correspondent

How quickly things have changed, again.

Further swathes of England have been moved up into tier four, the tightest level of restrictions.

Many other areas will see tighter rules as well, including where rates were seen to be relatively low.

Ministers are obviously anxious not to change arrangements around Christmas any further so the new restrictions will kick in on Boxing Day.

Given how serious Matt Hancock has said the situation is, he may face questions as to whether any household mixing should be allowed in just two days' time.

Dr Harries is now talking through the latest data illustrated in a set of slides.

She starts by saying cases have continued to go up at a “very rapid pace” in the last week, particularly in London, the south east and east of England, which entered tier four restrictions last weekend, as well as parts of Wales.

She says the rate of change is also stark in areas bordering tier four areas, such as Suffolk, Norfolk and the south-west of England.

Focusing on areas that are set to go into tier four, she says they are following the same case trajectory as areas already in the highest tier of measures and that this is down to the new variant.

Image source, COBR

Image source, PA Media

Hancock now delivers a series of thank yous including to those who work in the NHS and scientists helping to deliver the vaccine.

"I know how hard 2020 has been for everybody," he says.

"We mustn't give up now," he says adding "we must suppress the virus until a vaccine can make us safe."

"There are brighter skies ahead."

Turning to testing, Hancock says all those who work in care homes in England will receive two rapid tests a week in addition to their weekly PCR tests.

He also says the Oxford-AstraZeneca vaccine has submitted its full data package to the MHRA for approval.

And the UK has begun vaccinations in care homes. This includes the Chelsea pensioners, he says.

Image source, Science Photo Library

Hancock now says there are two cases of another new variant in the UK.

Both are contacts of cases who have travelled from South Africa.

"We are incredibly grateful to the South African government for their science," he says.

"This virus is yet more transmissible and appears to have mutated further than the new virus."

He says the UK is quarantining new cases, and placing restrictions on travel from South Africa.

Anyone who has been in South Africa in the past fortnight and anyone who is a close contact of someone who has been in South Africa in the last fortnight must quarantine immediately, he says.

Matt Hancock says tier three is not enough to control the new variant.

From 00:01 on Boxing Day, Sussex, Oxfordshire, Suffolk, Norfolk and Cambridgeshire, those parts in Essex not already in tier four, Waverley in Surrey, and Hampshire - including Portsmouth and Southampton but with the exception of the New Forest - will be escalated to tier four.

Bristol, Gloucestershire, Somerset (including the North Somerset area), Swindon, the Isle of Wight, the New Forest and Northamptonshire, as well as Cheshire and Warrington, will be escalated to tier three.

Cornwall and Herefordshire will be escalated to tier two.

More of the east and south east of England will enter the toughest Tier 4 restrictions on Boxing Day, Health Secretary Matt Hancock has announced.

The health secretary says he will set out details of new actions he is planning to take.

First he acknowledges that these actions are difficult but necessary.

He says cases have risen by 57% over the past week and hospital admissions are at 1,909 a day - the highest figure since mid-April.

Matt Hancock begins by saying that 2020 has been a hard year and is "ending in this festive period which is going to be very different".

He says: "Just as we have got a tiered system in place, we have discovered a new more contagious virus, a variant which is spreading at a dangerous rate."

The Downing Street press conference has started, with Health Secretary Matt Hancock taking to the lectern.

The UK government has been urged to declare a "state of emergency" in Kent, where more than 5,000 lorries remain stranded following the closure of the French border.

The Liberal Democrats, the fourth largest party in the UK Parliament, said ministers should invoke powers in the 2004 Civil Contingencies Act to stop the situation "spiralling out of control" and to ensure lorry drivers were able to get food and wash.

Its leader Ed Davey said action was also needed to roll out testing at Dover, to unblock the road network and support local residents.

"Boris Johnson must recognise the crisis in Kent has got out of control and show some leadership," he said.

“Without food and access to sanitation, people are in real trouble. If ministers fail to act now and commit the resources needed now, they risk things spiralling further out of control."

Many countries have banned flights to the UK but a number of nations have now announced plans to reinstate them:

• Switzerland will allow flights to Britain to resume on Thursday

• Bulgaria is permitting flights from the UK from Wednesday in order to help those wishing to return home. Travellers from the UK will be tested for the virus and will have to observe a 10-day quarantine

Separately, France and Britain have resumed cross-channel travel as long as those entering France can show a negative Covid test less than 72 hours old, AFP reports

UK Health Secretary Matt Hancock to due to lead a Downing Street press conference at around 15:00 GMT.

He's expected to announce changes to some tier restrictions in England.

He will be joined by deputy chief medical officer Dr Jenny Harries and Dr Susan Hopkins of Public Health England.

Image source, Getty Images

The military has been drafted in to help carry out rapid tests on thousands of stranded lorry drivers.at the UK border with France.

From Wednesday, 170 personnel will support NHS Test and Trace staff in Kent.

Around 50 countries imposed a ban on British travellers after the UK warned of a new, fast-spreading variant of coronavirus.

France has since ended its ban on UK arrivals - but those wishing to travel can only do so if they can provide a recent negative coronavirus test.

With more than 5,000 lorries being held in Kent, the military has been called in to help speed up the testing process and get hauliers stuck in Kent on their way again.

The work is not new to the soldiers. Many were previously called upon to adminster lateral flow tests in Liverpool, Medway and Merthyr Tydfil.

While the new variant of coronavirus is now "everywhere" in the UK, restrictions over Christmas should slow its spread, a scientist advising the government has said.

Prof Neil Ferguson told the Commons Science and Technology Committee: "Schools are now shut, we are in a near-lockdown situation across the country, contact rates are lower over Christmas.

"I expect, though I hesitate to make any sort of predictions, we will see a flattening of the curve in the next two weeks. We will see at least a slowing of growth."

However, he said the "critical question" was what happens in January, "and the extent we want to make public health measures more uniform across the country if the new variant is everywhere".