The first question from the public is from Gethin in Warwick, who asks if schools could move to remote learning for the final week of this term, so staff and families would have fewer risks ahead of Christmas.

Boris Johnson says: "We want to keep young people in schools as much as we possibly can."

He says learning remotely can be a good thing, but then adds: "We want to see kids in school to get the benefits of learning... we want to see exams going ahead."

Image source, PA Media

Chris Whitty now talks through an animation which he says shows the infection coming down in many areas.

He explains the factors which inform the decision to put certain areas into certain tiers.

This includes the rates of infection in people over 60, the rates at which things are changing, and pressures on NHS hospitals.

He says tier-one restrictions were able to "slow things down but did not stop the rise anywhere".

Tier two stops infections rising and tier three is strong enough to pull things down from a higher peak, he adds.

Image source, PA Media

Sir Patrick Vallance, chief scientific adviser, shows data on the number of people testing positive for Covid.

He says cases started to increase in September. When tiers were first introduced, the rate of increase continued - but then started to come down a little.

He said tier one did not seem to slow increases in rates, where tiers two and three did. In some tier-three areas, there was a decrease in cases.

Vallance says it looks as though there has now been a flattening of cases, following the introduction of national restrictions. Cases are no longer going up and it looks as though they are starting to go down.

Cases have "turned the corner", he says. He adds he would expect to see a potential decrease in cases in the next few weeks.

But with the latest data showing one in 85 people has the virus, cases are still high.

Image source, Getty Images

The UK government will lift its travel ban on Denmark from 04:00 GMT on Saturday, Transport Secretary Grant Shapps has announced, external.

However, the country will not be added to the UK's travel corridor list - so arrivals will still need to self-isolate.

The UK imposed a ban on non-UK citizens coming from Denmark earlier this month, amid concerns over a new coronavirus strain that has spread from mink to humans.

Image source, PA Media

Boris Johnson says mass community testing in Liverpool has helped reduce the number of cases by two thirds.

He describes it as a "success story" and says community testing will be offered to tier-three areas "as quickly as possible".

"The data is beginning to improve but the virus is prevalent," says Johnson.

"The faster we can drive it down the faster we can lift the restrictions - and that is what the tiers are designed to achieve."

He says the previous tiers system slowed infection rates but "were never quite enough".

He explains that the new approach is "designed to reduced the R rate below one".

Arrivals to the UK from Estonia and Latvia must self-isolate from 04:00 GMT on Saturday, Transport Secretary Grant Shapps has announced.

However, he said Bhutan, Timor-Leste, Mongolia, Aruba and the Pacific Islands of Samoa, Kiribati, Micronesia, Tonga, Vanuata and the Soloman Islands had been added to the UK's travel corridor list.

Arrivals to the UK from these destinations after 04:00 GMT on Saturday do not need to self-isolate.

Johnson says data is positive but warns that "if we ease off now we risk losing control of the virus all over again" and that, he says could open the way to a "new year lockdown".

He says the "tough measures in our winter plan are the best way to avoid this outcome".

He then lays out details of the new tier system in England, apologises that so much of the country will be living under the strictest restrictions and acknowledges this will cause "heartache and frustration".

Image source, PA Media

Prime Minister Boris Johnson begins the briefing by saying: "We have reason to hope that, by spring, community testing and vaccines will combine to end this era of restrictions."

"But to get there we must first navigate a hard winter when the burden on our NHS is heaviest," he adds.

The Downing Street press briefing is starting, with Prime Minister Boris Johnson at the podium.

Chris Mason
Political Correspondent

Few things have been predictable during this pandemic.

But here's one thing that has: when the prime minister brings Professor Chris Whitty and Sir Patrick Vallance along to a news conference, you can be sure he thinks he's got something pretty important to say.

Boris Johnson has been enjoying his first day in the best part of a fortnight being able to actually leave Downing Street.

He was in the Commons earlier to sit at a social distance from the Health Secretary Matt Hancock, as Mr Hancock announced which areas would be in which tiers in England.

But he'll be back in No 10 shortly alongside his chief medical adviser and chief scientific adviser, as the phrase "next slide please" returns to our airwaves.

We're expecting a Downing Street press briefing at around 17:00 GMT.

It will be led by Prime Minister Boris Johnson, who will be joined by England's chief medical officer Prof Chris Whitty and chief scientific adviser Sir Patrick Vallance.

Expect to hear more from the prime minister about the new tier restrictions for England when the national lockdown ends next week.

Santa Claus has been deemed an essential worker and will not be subject to coronavirus travel restrictions when he arrives in Ireland next month.

Minister of Foreign Affairs Simon Coveney confirmed the government's decision to the Dail parliament on Thursday. He said Father Christmas had confirmed to the authorities he intended to fly to Ireland on 24 December as usual.

But Mr Coveney said children should stay in their beds that night as Santa had to socially distance.

"As minister for foreign affairs we've been working on the Santa Claus issue for a number of weeks now," said the minister.

"And it's important to say to all children in the country that we regard Santa Claus's travels as essential travel for essential purposes and therefore he is exempt from the need to self-quarantine for 14 days and should be able to come in and out of Irish airspace - and indeed in and out of Irish homes - without having to restrict his movement.

"So he's exempt, he's coming, he's confirmed that, and he appreciates the fact that Ireland has ensured that in a very, very different Christmas in 2020, the visit of Santa Claus will be something that will remain consistent."

UK Prime Minister Boris Johnson is due to lead a Downing Street press briefing at 17:00 GMT.

He'll be joined by England's chief medical officer, Prof Chris Whitty, and chief scientific adviser, Sir Patrick Vallance.

While we wait here's a quick recap of the main UK stories today:

• Most of England will be in the two toughest levels of restrictions when the national lockdown ends next week
• The hospitality industry has warned tens of thousands of businesses will be forced to close permanently without extra support
• Coronavirus infection rates in England are continuing to show signs of levelling off - but the picture across the UK is mixed, according to data from the Office for National Statistics
• In Scotland, the government has announced that Christmas "bubbles" of three households should contain no more than eight people over the age of 11

Image source, Getty Images

We've been answering some of your questions about who you can meet over the Christmas period across the UK, after the rules were published yesterday.

My husband and I will be on our own over Christmas/New Year but want to see family before they fly home to America. Can we choose our own dates - say 15-19 December - as we won't be seeing anyone after that?

No, you would not be allowed to do this, as the Christmas bubble rules only cover the period from 23-27 December in England, Scotland and Wales, and 22-28 December in Northern Ireland.

However, depending on where you live in the UK, you will almost certainly still be able to meet up, but probably not all at once and almost certainly only outdoors, unless you are in a support bubble, or live in a tier-one area.

From 2 December, the rule of six will apply to meeting people outdoors in England - the same as in Scotland and Northern Ireland, and in Wales the limit is four people outdoors. Meeting indoors with people outside your household or support bubble will only be allowed in tier-one areas of England and very limited parts of Scotland.

Does a university student returning home at Christmas count as a single household while they are home with you?

No, they won't count as a single household over the festive season.

The government guidelines say that once a student moves home for the holidays, they are counted as part of the household to which they have returned., external

During the holidays, they no longer count as part of their term-time household.

We've answered more of your questions about Christmas and other coronavirus topics here. Or read our explainer for more detail about the rules over Christmas.

A further 17,555 coronavirus cases have been recorded in the UK, along with 498 deaths within 28 days of a positive test, according to the latest government figures.

The number of daily cases is down from 18,213 on Wednesday, while the number of deaths is down from 696.

Image source, Reuters

More than one million people passed through airports in the US yesterday ahead of Thanksgiving celebrations, the country's Transportation Security Administration (TSA) says.

While fewer than the same day last year, the 1,070,967 travellers is the highest daily figure recorded since the start of the outbreak in the US months ago.

President-elect Joe Biden earlier urged Americans to modify their Thanksgiving celebrations, while acknowledging that events would look very different this year.

The annual Macy's Thanksgiving Day Parade in New York - as important an occasion as serving turkey for many in the US - has been limited to a televised event, with increased security to help prevent a build-up of spectators.

Image source, Reuters

However, in the early hours, people were already beginning to show up alongside barricades on the streets of Manhattan.

Image source, Reuters

Many families have said that they will be spending time with their loved ones virtually this year.

Biden said that he would experience the day differently, too. Instead of the usual large gathering he would be spending the holiday with just his wife Jill and their daughter and son-in-law, while the rest of the family would be in small groups, he said.

US President Donald Trump, meanwhile, said in a statement: "I encourage all Americans to gather, external, in homes and places of worship, to offer a prayer of thanks to God for our many blessings."

Nick Triggle
Health Correspondent

Image source, PA Media

With England's lockdown coming to an end, it's all change.

A new system of regional tiers will come into force next week. That will be followed by a relaxation of rules at Christmas across the UK which will allow up to three households to meet over the festive period.

But scientists are warning the move risks a third wave of Covid. So is the government making a mistake?

Our health correspondent Nick Triggle looks at the evidence.

Case rates in the over 60s are just one of the critical numbers that the government is looking at to determine which tier an area should fall into.

Many areas of England have seen falls in the number of cases among the over 60s since the beginning of lockdown but in 39% of council areas the rate has risen.

Particular areas of note are in Kent and Lincolnshire – both areas that face the most severe restrictions from 2 December.

Between the 14-20 November East Lindsay in Lincolnshire saw 575 cases per 100,000 people - the highest in England. This is more than double the number it had in the seven days before lockdown.

Tunbridge Wells had the largest rise. Its cases per 100,000 in the over 60s more than quadrupled during lockdown. The good news is that in both areas the most recent data shows that cases are beginning to fall.

Mayor of London Sadiq Khan said it was the "right and sensible decision" to have the city under tier two restrictions.

He said Londoners had made "monumental sacrifices" over recent weeks and months.

He reminded people they are still in lockdown til next Wednesday - with restrictions still in place, but it does mean Londoners can visit the shops, bars and restaurants "who desperately need custom".

It is crucial to still follow the rules as "the virus is still there, still spreading", and "people are still losing their lives".

Being in tier two "doesn't mean a free-for-all" and "doesn't mean we can act as we did before the pandemic", Khan added.

He said he hoped London could at some stage move to tier one - but warned there was a risk the city could also move to the higher restrictions of tier three.