Martyn Rooney is a very disappointing fifth in his heat in a time of 45.60 seconds. That is unlikely to be good enough to qualify. Oh dear. 

Martyn Rooney goes for GB in the next heat. He's been around for ever, or so it feels. Top three in each heat go through. 

'...I think you're in my seat.'

Image source, Getty Images

World champion Wayde van Niekerk jogs to a win in his heat in 45.26 seconds. That was super easy. 

I forgot to mention that a jump of 8.15m will qualify automatically for the final - failing that it's the best 12. 

British tennis player Laura Robson is enjoying the men's doubles final as Romania's Florin Mergea and Horia Tecau are taking on Spanish pair Marc Lopez and Rafael Nadal.

It is one set all, with the Romanians 4-3 and a break up in the third set.

Greg Rutherford has moved away from the rest of the competitors and is camping. Lying in a sleeping bag with a can of red bull.

Get in the stands Greg - there's loads of room!

World champion Wayde van Niekerk goes in the next heat. Let me remind you he has done 9.98 in the 100, 19.98 in the 200 and 43.48 in the 400m.

He'd win the British champs in all three!

Steve Backley
Four-time European javelin champion on BBC TV

That was an absolute mess, she’d have done better with a standing throw.

Fair to say Steve isn't impressed with KJT's attempts in the shot put... 

Image source, Reuters

GB's Laura Muir and Laura Weightman both qualify for 1500m semi's.

Watch how below.

Katarina Johnson-Thompson's horrowshow of a shot put has left her in sixth place after three events, but Jessica Ennis-Hill is now second.

Belgian Nafi Thiam leads. 

The second heat is won in a super impressive run of 45.16 - jogging - by Bralon Taplin of Grenada. 

Katarina Johnson-Thompson up for her final throw - and it's just 11.19m!

Change of lead time...

Jessica Ennis-HIll had her head in her hands after that final throw of 13.86m. Not brilliant. She has the 200m to come of course.

To add insult to injury Nafi Thiam of Belgium has just launched one 14.91m!

She will go into gold medal position!

Image source, Reuters

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

This year has shaped up to be a fantastic year for the 400m. I know who will win the medals, or who I believe will, but I don't know the order. In these early rounds we will see people get some kinks out.

That's a quick first heat! There were 18 PBs in the women's 10,000m so maybe this is a mythical 'quick track' after all.

Machel Cedenio wins it for Trinidad & Tobago in 44.98 seconds. 

Now or never for Jessica Ennis-Hill in her shot put, she needs a good throw. And she hasn't got one.

It's not a disaster, but it's only 13.86m. That will give her 785 points.

Martyn Rooney of GB goes in the fourth heat of tonight's 400m, but realistically he is unlikely to challenge for a medal.

World champion Wayde van Niekerk of South Africa goes in heat three and is perhaps the ultimate all-rounder.

In March he became the first athlete to run under 10 seconds at 100m, sub 20 for 200 and under 44 for 400m. Wow!

Image source, Getty Images

However he is only the third-fastest man over one lap this season, with defending champion Kirani James and LaShawn Merritt topping the timesheets.

Merritt - champ in 2008 - is the only man to run a time in the 43 seconds this year.

Merritt is in heat five, while James goes in heat six. 

Heat one starts. NOW

There's lots going on in the stadium tonight. Greg Rutherford goes for qualification in the long jump which starts in 15 minutes.