The Portuguese have dropped the baton!

It is fight between USA, Botswana and South Africa for the medals now...

As expected, it is a battle between USA and Botswana for the gold.

Can Lewis Davey move GB into bronze contention?

The Americans have splashed their way to first place from the utterly swamped inside lane.

GB are fifth after two legs.

Lee Thompson has GB in second after the first leg.

He safely hands over to Toby Harries.

Despite the conditions, we are under way in the first of the relay finals.

GB are in lane nine, the very outside track to start.

It really is horrendous conditions in Tokyo.

Looks like Manchester did yesterday.

Image source, Getty Images

The USA are the Olympic champions and have won this world title in nine of the past 10 attempts.

But their additional race this morning could play into the hands of Olympic silver medallists Botswana, who had three men in the 400m final – including the gold and bronze medallists.

And will the torrential rain prove a leveller?

Lee Thompson, Toby Harries, Lewis Davey and Charlie Dobson are the British team in the men's 4x400m final.

One change from the team which qualified from the heats, with Davey replacing Seamus Derbyshire.

Harry Poole
BBC Sport in Tokyo

I'm not sure how much this is coming across on your TVs, but it is absolutely battering it down in Tokyo.

The track is beginning to flood!

Chaos does not begin to describe the men's 4x400m relay heats - to the extent that we didn't know until this morning who all the finalists would be.

The United States and Kenya contested a shoot-out men's 4x400m to qualify for the final after Zambia were disqualified for an infringement.

The USA, the Olympic champions who have won this world title in nine of the past 10 attempts, won that head to head and progressed to the final.

Their getting a second chance after a muffed changeover which cost them in the heats could change everything.

Great Britain are there too, but Paris 2024 silver medallist Matthew Hudson-Smith is not fit enough to come into the line-up.

Image source, Getty Images

The rain is now absolutely pouring down in Tokyo, and stadium staff are desperatly trying to apply towels to the discus thowing area.

We just saw Australia's Matt Denny slip over mid-throw, it is quite dangerous conditions. The competition has now been paused.

Will the weather have an impact on the upcoming relays?

Image source, Getty Images

Image source, Getty Images

Georgia Hunter Bell speaking to BBC Sport after her silver medal in 800m final: "I wanted to show what I can do in the 800m and I knew I had to come into it fresh if I wanted to get a medal and doing both [800m and 1500m] would be too hard. The competition is so good.

"I'm so happy, the fastest time I've ever run. I knew it would be fast from seeing the girls in the field but I was just like 'don't get dropped' and try to hang on to get the kick in the end."

Image source, Getty Images

Keely Hodgkinson speaking to BBC Sport after her bronze medal in the 800m final: "I felt pretty good at the start and it was quick out there and a bit of tussling and surging that might have wasted a bit of energy but I was in it to win it, and when you go in for gold, you risk dropping off the podium or coming second or third.

"I'm happy for the both of us [Georgia Hunter Bell] we both got a medal, my third 1:54 and to be consistent like that, especially after the year I've had, it's not what I came here for but I can't be too disappointed."

On the final stretch: "I thought I had it. But [Lilian] Odira ran past and I did my best. The last 10m my legs were falling off. I ran it how I ran it and this is what the result is."

Colin Jackson
Two-time world 110m hurdles champion on BBC Radio 5 Live

Colin Jackson on Lilian Odira of Kenya securing gold in the women's 800m final: "She had what I describe as a balanced race. She saved her energy and kept everything nice and smooth. When she made the move from 110m she was full of energy compared to the others."

Image source, Getty Images

Although there are no Brits in the men's discus final, it'll still be an exciting watch.

Defending champion Daniel Stahl of Sweden, 2022 world champion Slovenian Kristjan Cej and world record holder Mykolas Alekna of Lithuania are all on the hunt for gold in today's final.

Olympic bronze medallist Matt Denny of Australia is also in medal contention.

British record holder Lawrence Okoye was unable to join them after placing 15th in qualifying, outside the top 12 who progressed to the medal event.

Image source, Getty Images

A slightly disappointing Sunday so far, but there are still British chances for medals today.

Here's when you need to be in front of the TV/reading the live text:

12:20 - Men's 4x400m relay - GB team

13:06 - Women's 4x100m relay - GB team

There won't be a medal for Great Britain in the women's high jump.

Morgan Lake has failed her third attempt at 1.97m - three centimetres below her personal best.

Nicola Olyslagers, Yaroslava Mahuchikh, Angelina Topic, and Maria Zodzik are out in front following first time clearances of 1.97m.

Earlier, British duo Georgia Hunter Bell and Keely Hodgkinson were beaten to gold by Lilian Odira of Kenya in a dramatic final.

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images