The last event of the 2017 worlds is under way!

For the British men. Here's how the women did it.

GB have put Matthew Hudson-Smith out first in a bid to be 'in the hunt'. Not always best to stick your strongest man last.

Belgium have three of the Borlee brothers in their team.

Michael Johnson
Four-time Olympic gold medallist athlete on BBC TV

This British team has gotten stronger here with the addition of Matthew Hudson-Smith.

Great Britain have a great chance of gold because this American team are very weak to be honest.

Image source, BBC Sport

Here come the teams. Michael Johnson calls the United States team 'very weak.']

Now then...

David: MJ's doin his Morgan Freenan impression

The Collector: Michael Johnson aka Morgan Freeman

High jump winner Mutaz Barshim: "I really want to say thank you. I really wanted it! London is special place for me. It's where I had my first Olympic medal and the crowd was amazing.

"I love the pressure. That's when I perform the best. I expect from myself much more than everybody. It's motivation."

Image source, Getty Images

Rabah Yousif and Martyn Rooney were in the British team which won bronze in Beijing two years ago. Tonight, they go again.

Could GB end these games with six medals - bang on target?

Liverpool's Croatian centre back has congratulated compatriot Sandra Perkovic on her win tonight....

A reminder that the US have won this event in each of the last six world championships. The US women won it by six seconds. Gauntlet thrown down?

Britain did not qualify for the final at last year's Rio Olympics so they are hoping for a medal tonight.

The team is:

1. Matthew Hudson-Smith
2. Dwayne Cowan
3. Rabah Yousif
4. Martyn Rooney

Image source, Reuters

The elimination of pre-race contenders Botswana, Jamaica (the Olympic silver medallists) and London 2012 champions Bahamas has improved US chances of a seventh straight win.

The heats continued the rollercoaster ride for Isaac Makwala at these championships – in Makwala’s absence the Botswanan squad failed to qualify for the final.

GB face a tough battle to claim a medal with the likes of 2015 silver medallists Trinidad and Tobago andEuropean champions Belgium looking strong en route to qualifying second and third fastest respectively in the heats.

Steve Cram
BBC athletics commentator on BBC TV

The Brits ran slower than they did in the semi-final but its the racing that makes the difference.

That is a true team performance. You can only beat what is there and yes, Jamaica were not in it after that second leg but that was a real fight for the silver.

Image source, getty

Allyson Felix now has 11 world gold medals, the same as Usain Bolt, but she now has 16 medals to his 14.

Image source, Getty Images

Great Britain finished third in Beijing two years ago, but only qualified as fastest losers and face a battle for a medal with the likes of Trinidad and Tobago and Belgium.

The United States look certain to secure a seventh consecutive victory in this event.

Image source, Getty Images

That's a fifth medal of the games for Great Britain. They profit from Jamaican relay woe for a second night in a row.

But a great effort all round.

The US won that by SIX seconds...

Emily Diamond was being closed down by Justyna Swiety of Poland but she hangs on!