I'm Anita McVeigh, and here at BBC News we are going to be keeping you right up to date throughout the day on all the developments in this crucial Ukraine war summit, which is taking place just a stone's throw from here.

In the words of the BBC's political editor, Chris Mason, the stakes for this summit are colossal.

After that extraordinary meeting in the Oval Office involving President Trump and President Zelensky on Friday, two obvious and huge questions.

One, will leaders gathered here today be focusing on trying to work out how they can patch up that relationship?

Obviously they will.

But also, plan B, what will they do if they can't fix those problems that we saw between President Zelensky of Ukraine and US President Donald Trump on Friday?

So a huge amount at stake today.

Well, we got some insight into the direction of travel a little earlier when the Prime Minister, Sir Keir Starmer, was speaking to the BBC's Laura Kunzberg.

He was asked for his reaction, first of all, to what happened in the Oval Office on Friday between Presidents Trump and Zelensky.

Clearly, you know, there's a lot of tension, the cameras were on, nobody wants to see that.

But I spoke to President Trump, I spoke to President Zelensky.

Obviously, we then had President Zelensky to Downing Street yesterday and I spoke to President Macron after that and then to President Trump.

And the purpose, or my driving purpose, has been to bridge this, if you like, and get us back to the central focus.

And as a result of the meeting yesterday, we had quite a long time with President Zelensky, then President Macron and President Trump on the phone.

We've now agreed that the United Kingdom, along with France and possibly one or two others, will work with Ukraine on a plan to stop the fighting and then we'll discuss that plan with the United States.

So, in those calls on Friday night, through the meeting yesterday, into the calls again last night, I think we've got a step in the right direction because, as I say, nobody wants to see what happened on Friday, but it's really important that we keep our central focus, which is lasting peace in Ukraine.

Nobody wants any more bloodshed.

And everybody wants to hear the details of what the proposals might be that you are trying to get agreed.

But what happens matters so much because it's about the trust and the relationship between the two men at the centre of this, President Zelensky and President Trump.

President Trump said it's difficult to do business like this.

He made it completely clear that he didn't have, in that moment, very much sympathy for Ukraine.

He was berating President Zelensky, telling him he should be grateful.

And I think, Prime Minister, anyone who's known you for a long time would have a pretty good guess that you would have felt deeply uncomfortable watching what played out, did you?

Yes, I felt uncomfortable.

Nobody wants to see that.

But the important thing is how to react to that.

There are a number of different routes people could go down.

One is to ramp up the rhetoric as to how outraged we all are or not.

The other is to do what I did, which is roll up my sleeves, pick up the phone, talk to President Trump, talk to President Zelensky, then invite President Zelensky for an extensive meeting yesterday, warm welcome, and then further pick up the phone to President Macron and President Trump afterwards because my reaction was, we have to bridge this, we have to find a way that we can all work together because, in the end, we've had three years of bloody conflict now.

We need to get to that lasting peace.

And I have to say, I've spoken to President Trump a number of times, I've met him twice, we had a long session on Thursday.

I'm clear in my mind that he does want lasting peace.

He does want an end to the fighting in Ukraine.

I'm absolutely clear that's what his motive is.

I agree with that.

President Zelensky agrees with that.

I think everybody agrees with that, apart from Putin.

And, in the end, that remains the central most important thing, which is why we took a step forward, in my view, last night when we agreed that we would work on a plan for stopping the fighting and then, as it were, discuss that plan with the United States.

That's a step forward from where we were on Friday and an important step forward.

Sir Keir Starmer, the UK Prime Minister, while Kemi Badenoch, the Conservative leader, was also asked what she thinks about Keir Starmer's plan for the UK and France to work with Kiev to stop the war.

I think we need to know, as you say, exactly what that means.

Last week, I did ask him, when he talked about putting British troops on the ground, where was the money coming from, what were the guarantees around that.

We certainly shouldn't be doing it on our own.

And looking at the scenes from last week, it's really important that this summit that the Prime Minister is having today goes well.

We support him in that.

This is a key issue of national interest for us.

There is not a difference between the Conservative and Labour parties in terms of the extent of support that we have for Ukraine.

People know what we did under Prime Minister Johnson and his successors.

And we want to make sure that the Prime Minister is successful in helping Ukraine, but also in maintaining our national interest at all times.

What did you think when you saw those scenes in the Oval Office on Friday night with President Trump berating President Zelensky?

Honestly, my heart went out to President Zelensky.

I watched it and I couldn't believe what was happening.

He was being humiliated.

I don't think we should conduct these sorts of difficult conversations in front of the cameras.

And we have to remember that President Zelensky is a hero.

He is the person who represents that strength and resilience of the Ukrainian people.

And whatever differences and difficulties we might have during negotiations, we need to be able to set them aside when everyone is watching, because the only person who would have liked that would have been Vladimir Putin.

Let me just tell you who is going to be at this crucial meeting today.

It's quite a list, which is why I've got it all in front of me, so I don't leave anyone out.

Just to say first of all that we are expecting the Italian Prime Minister, Giorgio Maloney, to arrive at Downing Street to that meeting, which is taking place at Lancaster House.

So there will be the leaders of Ukraine, France, Germany, Denmark, Italy, the Netherlands, Norway, Poland, Spain, Canada, Finland, Sweden, Czechia and Romania.

The Turkish Foreign Minister will be there.

The NATO Secretary General, Mark Rutte, will be there.

And the presidents of the European Commission and the European Council will be there.

So it is a huge gathering hosted, of course, by the UK Prime Minister, Sir Keir Starmer.