American Kerron Clement - a world champion in 2007 and 2009 - comes through in the final 50m to overhaul the fast-starting Javier Culson. Winning time of 48.40.

South African Lj van Zyl was back in fourth, with Jack Green the best-placed Briton in fifth with a time of 48.99. 

A quality field for the 400m hurdles.

Michael Tinsley and Javier Culson - second and third respectively at London 2012 - will be chased by Britain's Sebastian Rodger and Jack Green.

Katarina Johnson-Thompson has got the long jump field in a headlock.

The Liverpudlian's fourth leap of 6.84m has her at the top of the standings.

Shara Proctor is second with 6.80.

Jessica Ennis-Hill is lagging back in seventh with a best of 6.19m.

Michael Johnson
Four-time Olympic gold medallist on BBC TV

I'm mixed. Matthew Hudson-Smith did what he had to do. It wasn't a super quality field, but you can only win the race. It would have been good to see him under 45 seconds, which he has done earlier this year. That would have been good for his confidence.

Matthew Hudson-Smith, speaking to BBC Sport: "It was a bit new to me, three false starts, and I'm still a bit flat from finishing uni. 

"I didn't get out that well but I finished strong and got the win. Now it's time to start tapering, and on to Rio. 

"Anything can happen at championships. It's the day that matters. I didn't run to the best of my ability but I still won, so that's important preparation."

Image source, Getty Images

Darren Campbell
Former British sprinter on BBC Radio 5 live

It seemed Hudson-Smith had an elephant on his back when he got caught in the last leg of the relay at the Europeans. But he's moved forward today. That will help him regain his confidence.

Allison Curbishley
BBC athletics expert on Radio 5 live

I am surprised it wasn't slightly quicker. Hudson-Smith went through 200m really quickly and he looked great but he didn't have Martyn Rooney next to him to push him.

Matthew Hudson-Smith stretches out his legs over the final 60m to ensure his claim sticks.

It had been a bit of a crowd scene on the home straight, but he kept loose and limber under pressure to come through.

It was not the fastest race though. Hudson-Smith's winning time was a leisurely 45.03.

Rabah Yousif was third in 45.45.

Image source, Reuters

Steve Cram
BBC athletics commentator on BBC TV

I think that's harsh. It was a false start by Martyn Rooney but there was a ripple of applause from the long jump, which is always disconcerting. It's really sad for the European champion.

Martyn Rooney is a goner.

A ripple of applause when they were down in the blocks appears to have pressed the Briton's hair trigger.

False start and that is an immediate red card.

Image source, Getty Images

World silver medallist Shara Proctor leap-frogs to the top of the standings with a leap of 6.77m.

Katarina Johnson-Thompson is second with 6.63m.

Jessica Ennis-Hill can only improve by one centimetre and is down in seventh on 6.19m.

Image source, Reuters

Focus. Drive. Grit.

Serious single words. Moody black and white footage. No smiles.

That is how some sponsors like to sell their athletes.

It would not work with Matthew Hudson-Smith. The 21-year-old, a silver medalist at the Europeans in Zurich in 2014, is more clown prince than cold-blooded conqueror.

He is the fastest man in the field this year with a run of 44.88 seconds.

He is up against Martyn Rooney - the team-mate who beat him in Zurich two summers ago. Both are off to Rio this summer.

Take a look below at the two GB teams side by side as they near the finish line with the A team just edging it. Exciting prospects for Rio. 

Colin Jackson
Two-time world 110m hurdles champion on BBC TV

Dimitri Bascou this year is the man. He's had a cracking indoor season and has been running really well since the beginning of the year. But I feel he's not quite sighting the hurdles well enough - there are a few sloppy mistakes which must be frustrating. He'll be a threat in that final though, that's for sure.

That was the punchier of the two heats.

Dimitri Bascou wins it in 13.28.

Great Britain's Lawrence Clarke is fourth, but through as one of the three fastest losers.

Image source, Getty Images

Second heat over the barriers.

European champion Dimitri Bascou of France will take some catching.

Great Britain's Lawrence Clarke - back on the scene of his fourth-place finish in the London 2012 final - will give it a good go.

Colin Jackson
Two-time world 110m hurdles champion on BBC TV

Andrew Pozzi will be very pleased with that. He and his coach have spent a lot of time training for this but he's been riddled with injury for so many years. Now he needs to produce that again in the final later on. He was nearly flawless.

The first attempts have been laid down in the sand pit.

Katarina Johnson-Thompson is top of the pops with a season-best leap of 6.63m.

Shara Proctor is second with 6.57m with Jessica Ennis-Hill back in fourth on 6.18m.

Image source, Reuters