Further talks will take place tomorrow.

Mitt concerns that the guidelines, as they stand will lead to a very significant rise in cases to leading medical journals have joined forces toe warn that easing the rules for a five day period over Christmas is rash on will cost many lives.

Labor has called today for the guidelines to be much clearer on tougher.

We start tonight with this report by our health editor, Hugh Pym.

Christmas mixing will be a big mist ake.

That's the bleak message from two publications representing health and medical leaders.

If the rules agreed by the U.

K's administrations, which allows some household mixing, aren't changed, they argue that virus cases will escalate on the NHS will be overrun.

The rial striking stark truth of the matter is that our health system is not going to manage if we allow the current trend to continue out on top of, uh, they're super spread event.

That will be these five days of Christmas with households three or more households meeting people will find it hard to stick to those rules.

But ministers were sticking to the line that people should make their own decisions within the rules set out.

We've got to trust the British people toe at responsibly to do the minimum that is necessary for them within their family situation.

But we should recognize it has been a very difficult year for many families.

Many families will want to come together, but the government at Westminster is facing calls to look again at the planned easing of restrictions over Christmas.

I say to everybody, Look at the evidence is it is the last two or three days have seen a spike in infections going up.

Notwithstanding the tiered system, we can't stand back and ignore that this needs to be reviewed.

It needs to be done pretty urgently now on.

Scotland's first minister suggested there might need to be a rethink.

It's important that we have that discussion across the four nations given family patterns across the UK, but I do think that is a case for us looking whether we tighten the flexibility that were given any further, both in terms of duration and numbers of people at meeting the politicians will have to gauge public opinion.

Spending time together was not going to be the best thing.

Joe has already canceled a Christmas trip to see his sister.

I think people just have to be sensible this year and really think deeply about what really matters to them.

But others have made plans they say will be hard to change the turkeys on order a £15 turkey.

If there's only Jill and I for Christmas dinner, that's a hell of a lot of turkey.

Two weeks.

You know you're happy to have your injection today.

Yes, vaccination centers air now up and running, including this one, that barnet Football Club, where they're hoping to get through 350 jobs each day, starting with the over eighties.

On the first appointments today, vaccination centers like this may have got underway, but it will take a least four weeks and two jobs to build up protection on the process of getting through.

The most vulnerable patients will take time, and doctors in this north London area are very concerned about the rising case numbers they're seeing now.

It is a phenomenal threat.

It is very, very worrying the number of cases that results that were coming in with patients being covert positive on actually unwell, especially at this time of year when we had the easing of the lock down.

People are mixing with each other mixing with families.

Um, you know it's rising.

Some European countries air tightening up in response to hire infections that allowing a little leeway over Christmas.

The U.

K's governments will continue talks tomorrow on how to strike the balance.

Hugh Pym, BBC News.

Let's go live to Westminster and talk to our political correspondent Chris Mason.

Chris, as we know the talks to take place tomorrow.

Are you detecting any signs there that there could be changed to these Christmas rules?

I think those were changed you in tone, but perhaps not a change in the law.

It's been the central dilemma for political leaders here in the UK How he did around the world throughout this pandemic toe manage that balance between robbing us of the liberties that we take for granted and protecting us from the virus.

And what to do over Christmas is the ultimate example of that.

Political leaders are really conscious that they don't want to robbers of that precious chance to see loved ones that that would be a cruel end to a cruel year on.

Yet we heard that the warning from the medics that, frankly, this relax ation could cost lives.

So what on earth of the governments around the UK do they met earlier this evening?

There seems to be in agreement that they will shift the tone, the messaging.

That way we'll hear from them.

So they will say that the rules are a limit.

They're not a target.

If you're going to see vulnerable people over Christmas.

Elderly people, those who are clinically vulnerable change your behavior now, restrict how many people you're meeting.

If you live in an area with a lot of the virus about, think carefully about leaving that area.

Stay local if you can, so that will be the emphasis in the coming days.

The new approach isn't yet signed off.

There'll be another meeting tomorrow involving the government here on the government's around the UK, but expect that to be what we hear from the prime minister in the coming days on from the devolved leaders as well, Chris Once again, many thanks, Chris Mason there, Our correspondent at Westminster.

Well, now, under the Christmas rules, as they currently stand, agreed by the four home nations families will be able to travel across the UK on three households will be allowed to gather under one roof.

But as we've heard, many experts believe that these guidelines will provide the perfect conditions for a significant rise in cases are signs that is that David Shipman examines why it's a precious time of year for restoring morale on scientists researching the virus recognize that.

But they also know that spending long hours in packed rooms is the most effective way to spread it.

On the one hand, schools will be closed over the Christmas break, along with most workplaces, and that should help to reduce infections.

But on the other hand, having more people gather indoors is bound to increase transmission.

This animation by an industrial modeling company, simulates someone infected.

Researchers are worried.

I think there's a big risk over Christmas off essentially transfer of infection from younger groups with more contacts into older age groups who might not usually have this level of mixing, especially in this kind of year, and even in normal years, we do see an increase, um, in in hospitalizations for things like pneumonia after the Christmas period.

The rule across the UK is that three different households conform what's called a bubble over the Christmas period and shouldn't be mixing with people outside it.

Now, scientists say that it's within homes that the virus spreads most easily because people are so close together.

On average, someone infected may pass the virus 23 others.

So the more people in a bubble, the greater that risk.

Another worry is after Christmas, when people who are newly infected return home to other parts of the country and start mixing with friends and family there.

After the American holiday of Thanksgiving last month, with four million people traveling, health officials are watching for signs of a new surgeon infections.

British scientists say that their studies show keeping gathering small will make a big difference.

It's easy to imagine a kind of terrible scenario, but actually, when you start modeling it, you can then start thinking about how you would balance these, increase the increased risks somewhere else and how if, um, people who don't need to form a Christmas bubble decide not Thio.

How that actually improves the overall situation.

And if you do get together, open the windows.

This animation shows how fresh air helps to disperse the virus.

No one could be sure of the impact of the Christmas break, but there are ways to reduce the risks.