Image source, AFP

For all the joy, disappointment, anger and disbelief, it's worth remembering that there is life outside competition.

Aries Merritt, who won a bronze in the 110m hurdle on Friday, spoke earlier to Gabby Logan, about his upcoming kidney transplant on 1 September. 

"Me being here was a distraction from what is pending. I have been able to focus on winning a medal and not think about the operation.

"I have had to modify my training, training is incredibly difficult to recover from, I can't eat as much protein as I would like, I can't process potassium to combat cramps, oxygen can't get to my muscles properly and I am anaemic.

"Having my heats a day apart has really helped me, if the races had been on the same day I wouldn't be here. It has been tough but I have pulled it off."

Thanks for joining us today.

First leg - Richard Kilty: "We were easily in the running for a bronze. I don't know what went on in the third change. It's not a team we've practiced a lot. We messed up on the third change."

Second leg - Daniel Talbot:  "We win as a team, we lose as a team. It's not just us four here. It would've been nice to bring back a medal for everyone. We need to sort this out in the global championships and make sure we get it right for Rio next year."

Third leg - James Ellington:  My speed (going into the changeover) was OK, I need to watch it back. Maybe CJ went a bit early."

Final leg - Chijindu Ujah: "I felt like I went late. I didn't even get away to a fast start."

The moment Usain Bolt crossed the line to win his 11th world gold - and win gold for Jamaica.

Image source, BBC Sport

Steve Cram
BBC athletics commentator

Image source, BBC Sport

He's used to all this, but no doubt this moment on the podium is as special as all the others.

Image source, BBC Sport

Why were they disqualified? Mike Rodgers did not take the baton in time before he crossed the yellow line. 

So China take silver - what a result for the home team. And Canada are handed bronze - in doing so they have achieved their best ever haul of six medals.

Usain Bolt wins his 11th world gold having cruised through the final leg. He crossed the line in 37.36 seconds.

 USA took silver in 37.77, with Mike Rodgers on the final leg (although it did not look like a clean exchange).

And China... yes China take bronze in 38.01.

Great Britain? Oh Great Britain. 

They were in bronze medal position going into the final leg, but the exchange between James Ellington and Chijindu Ujah... well... did not happen.

Image source, BBC Sport

Tune into BBC One and click on the video link on this page now.

Image source, BBC Sport

"Contenders ready?"

The men's teams come through the double doors, into the Bird's Nest arena and face the camera - touch of Going for Gold too.

USA's Mike Rodgers, on the final leg, folds his arms and looks at the camera.

The Jamaica team put their hands together in unison and bow - I think more suited to a Japanese audience guys. 

The Canada team just embarrass themselves - arms folded in some bad 1990s pop combo style.

Image source, BBC Sport

Image source, BBC Sport

A reminder of the British quartet. Chijindu Ujah comes in for the rather unhappy Harry Aikines-Aryeetey, who was part of the group that helped GB qualify for the final.

Whatever you do, don't drop this. The final event of the day is coming right up: Bolt, Gatlin, Gay etc

Image source, Louise Bloor

Shelly-Ann Fraser-Pryce brings the baton home first as Jamaica complete the sprint lap in a championship record of 41.07 seconds.

The USA took silver in 41.68 and Trinidad and Tobago took bronze in 42.03.

Great Britain were fourth but... but... set a new national record - 42.10.

Excellent work all round.

Image source, BBC Sport

Two more finals to go. The USA and Jamaica are hot favourites. Can 200m champion Dafne Schippers inspire the Dutch team?

Dina Asher-Smith, unsurprisingly, comes in and Bianca Williams makes way for Great Britain.

The quartets have just come out in the way the Gladiators used to come out on the former ITV Saturday evening show.

A reminder of the GB quartet:

We reported earlier that Harry Aikines-Aryeetey was the one who made way for CJ Ujah in the GB team for the 4x100m relay final.

He has been retweeting others' shock at his exclusion. It's his 27th birthday today too.

Ashton Eaton is slumped against the scoreboard showing his WR total. The thing is he needs to get out of the way because we've got the sprint relays coming up - you know, Bolt v Gatlin: Episode III.

Two British teams in the women's and men's finals. 

Image source, Getty Images

Daley Thompson
Two-time Olympic decathlon champion on BBC TV