GREAT Britain's shambolic recent record in the men's 4x100m relay continued last night as the hosts were disqualified from their Olympic semi-final.

The British sprint relay team have now failed to successfully complete a race in five of the last six major championships, a dreadful run that raises serious questions about the level of preparation overseen by head coach Charles van Commenee.

They managed to retain control of the baton last night, an improvement on their most recent outing at the European Championships, and initially finished second behind a Jamaican team lacking the rested Usain Bolt.

However, 18-year-old Adam Gemili was shaking his head as he crossed the line, fully aware that he had been outside of the permitted area when he received the baton from fellow youngster Daniel Talbot ahead of the final leg.

“I know we like to play the blame game in our country, but as far as I'm concerned there's no one to blame here,” said Christian Malcolm, who ran the first leg before handing on to Dwain Chambers. “We've gone out there with two exceptional youngsters and I think it would have been only the fourth time we'd run under 38 seconds. We've got some youngsters in the team who can gain from this experience and it all bodes well for the future of British sprinting.”

Be that as it may, the lack of a British presence in tonight's 4x100m final, the final race of the track-and-field programme at London 2012, is a considerable embarrassment.

The British team was not finalised until a month or so ago, and the lack of preparation time must surely have contributed to last night's debacle.

The wisdom of combining the two most inexperienced members of the team in the most pressurised final changeover must also be called into question.

“People will ask whether he (Gemili) should have gone on the last leg, but at the end of the day, he's the best in our country right now,” said Malcolm. “You saw that once he got the baton in his hand.

“We've done a lot of practice. I think we got enough practice in. I know it sounds a bit repetitive, but it is just one of those things.

“We have a kid (Gemili) with exceptional talent, which is something we've been waiting for. He didn't freeze on the big stage – he rose to the occasion. He went away exceptionally hard, which he wanted to do, but unfortunately Danny couldn't catch him. But both guys ran extremely well under a lot of pressure.

“Of course we're gutted. We've gone under 38 seconds and that was with Adam having to stop and start again. Imagine what we would have done if the check mark was fine.”

The British men's 4x400m relay team has a much better recent record, and were unfortunate not to claim a medal in their final as they finished fourth.

After Conrad Williams produced a solid enough start, Jack Green's strong second leg thrust the British team into the medal mix.

Dai Greene, who was promoted to the line-up after sitting out the heats, finished the third leg in fifth position, but while Martyn Rooney immediately moved up a place into fourth, he was unable to overhaul the team from Trinidad & Tobago despite producing an excellent last leg.

There was a shock at the front of the field, as Bahamas' Ramon Miller overhauled American Angelo Taylor to claim his country's first Olympic gold medal of any description.

Britain's women's 4x400m relay team should also be in the mix for a medal tonight after qualifying in the third fastest time from last night's semi-finals.

The United States and Russia will almost certainly battle it out for the gold medal, but the British team of Shana Cox, Lee McConnell, Eilidh Child and Christine Ohuruogu will fancy their chances of pipping Jamaica and Ukraine to the bronze.

All four performed strongly last night, with Cox in particular catching the eye with a powerful lead-off leg and Ohuruogu running well within herself as she held off the final runner from Czech Republic to secure an automatic final spot.

Britain did not have a team in last night's women's 4x100m relay final, but the race will still live long in the memory after the United States set the second world record of the Olympic athletics programme.

The US quartet of Tianna Madison, Allyson Felix, Bianca Knight and Carmelita Jeter sliced more than half-a-second off the previous record, which had been set by East Germany in 1985, as they trounced their anticipated rivals from Jamaica in 40.82secs.

Felix added a relay gold to the individual 200m crown she claimed on Wednesday night, while Jeter leaves London with a gold, silver and bronze to her name.

Jo Pavey and Julia Bleasdale finished seventh and eighth respectively in the final of the 5,000m – a race that was won by Ethiopia's Meseret Defar – while Steve Lewis finished fifth in the pole vault and Sophie Hitchon came 12th in the final of the hammer.