It's a bad night for Great Britain - they finish last in their heat and are out of the women's 4x400m relay.

Yemi Mary John can't make up the time, as Jamaica take the heat with a year's best three minutes 22.77 seconds.

Norway set a national record to finish second ahead of Poland in third.

Over to Yemi Mary John for the final lap - can we work Great Britain back into contention?

The first place is going to be Jamaica's, but it's tighter for the following places.

Poppy Malik hands over to Nicole Yeargin as we head into the third lap, but it's not looking good for Great Britain's qualification chances.

Jamaica still hold the lead and it's stretching.

Victoria Ohuruogu lags a little after the first lap, and Poppy Malik has work to do after taking over.

Jamaica lead going into the second 400m.

Here we go with the women's 4x400m relay.

Great Britain are in the first of two heats, and start in lane four.

Victoria Ohuruogu will start the British team off.

Great Britain have earned world silver or bronze at nine of the past 10 editions and added Olympic bronze in Paris.

The team of Victoria Ohuruogu, Laviai Nielsen, Nicole Yeargin and Amber Anning got themselves on the podium last summer, and the Brits will hope for the same at least this time. Poppy Malik is in for Anning in this heat.

They are in heat one alongside Jamaica, who were runners-up at the past two World Championships but dropped the baton at the Olympics.

Heat two features Olympic champions USA, who were disqualified in the worlds heats two years ago after a botched final baton exchange - allowing Netherlands to go on to claim the title in Budapest.

Image source, Getty Images

There are no Brits in this final now getting under way, but plenty of global stories and intrigue.

USA’s Chase Jackson is seeking a hat-trick of world titles and her national record of 20.95m this year is the farthest throw in the world since August 2013.

She is safely through to the final after finishing second in qualifying this morning, behind Germany's Yemisi Ogunleye.

Canadian Sarah Mitton won world silver in 2023 but, like Jackson, endured a miserable Paris Olympics – coming last in the final. She was fifth in qualifying.

Gong Lijiao of China is seeking a ninth successive podium finish at a World Championships. She won back-to-back golds in 2017 and 2019, and came through qualifying in seventh.

The 12 best athletes from qualifying will compete for a medal this afternoon.

The javelin has come to an end in the heptathlon, and here's how we stand going into the final 800m event.

• Anna Hall (USA) - 5865 pts
• Kate O'Connor (Ire) - 5743
• Taliyah Brooks (USA) - 5662
• Katarina Johnson-Thompson (GB) - 5578
• Sandrina Sprengel (Ger) - 5555
• Sofie Dokter (Ned) - 5506

Great Britain's Jade O'Dowda is eighth with 5487.

Kate O'Connor has moved in front of Taliyah Brooks and Katarina Johnson-Thompson in the standings after topping the field with with a throw of 53.06m.

Brooks threw her own best of 43.37m, but is now in bronze position, while Johnson-Thompson slips out of the medal positions for now.

She'll look to return to the podium on the track at 13:11 BST.

Only fourth for the British team - but they are inside the three minute mark, quick enough to reach the final.

Botswana were impressive as expected, won that heat and are probably now the gold favourites.

Belgium and Australia are also through, while GB's 2:58.11 was quicker than South Africa, winners of heat one.

Promising for GB, you feel they could improve.

Botswana, Belgium and Australia are clear as the front three.

Can Charlie Dobson ensure GB are quick enough to qualify?

Toby Harries has moved Britain up to fourth.

He jostled with the Japanese runner there, but has left Seamus Derbyshire in a good position.

GB are sixth at the first changeover.

Toby Harries has work to do.

Away we go.

A huge roar from the crowd, as Japan run in lane three.

Botswana and Belgium were silver and bronze at Paris 2024 and will be strong here too.

Seamus Derbyshire, who will run the third leg for GB, blows a kiss to the camera.

Love you too, Seamus.

Demarius Smith and Bryce Deadmon were the American runners who mucked up their changeover and cost their country a shot at a medal.

We are sure Rai Benjamin, who surely would have come into the final team, will be having words.

Lee Thompson, Toby Harries, Seamus Derbyshire and Charlie Dobson are your British team in the men's 4x400m heats.

A reminder that a top three finish would guarantee a final spot - while 3:00.76 is the target to guarantee a fastest loser spot, as long as they come fourth or fifth.

Katarina Johnson-Thompson's final attempt is 41.91m, the best of the three but only puts her 15th in the event, and fourth in the overall standings with others still to throw.

Team-mate Jade O'Dowda manages a best throw of 46.20m with her final go.

Image source, Reuters

South Africa, Qatar and Netherlands have qualified for the final, while Kenya and China are in the fastest loser spots at present.

But this has blown the medal race wide open.

Can GB capitalise? They run in heat two.

How about this!

The USA are the Olympic champions and have won this world title in nine of the past 10 attempts. But after a horrendous mistake between two inexperienced runners, they have finished sixth in the heat and are out of the competition.

In to the final leg, the USA are in last place.

Could we see a massive upset?