World record for Jamaica

Usain Bolt brought the track action at London 2012 to a fittingly thrilling finale by anchoring the Jamaican 4x100m relay team to gold in a new world record time of 36.84 seconds.

The sprint superstar made it a hat-trick of Olympic titles for the second successive Games as he led his team-mates home before seemingly paying his own tribute to double Olympic champion Mo Farah by performing the 'Mobot' celebration after crossing the line.

Nesta Carter, Michael Frater and then double silver medallist Yohan Blake gave Bolt the lead he scarcely needed to hold off the United States in second.

Canada thought they had claimed bronze but were disqualified after Jared Connaughton ran outside his lane on the third leg, leaving Trinidad and Tobago to finish third.

Treble treble?

Bolt was asked if he could do the 'treble-treble' by winning the 100m, 200m and 4x100m again in four years' time, having achieved the feat first in Beijing and now in London.

He is not convinced it is possible.

Bolt said on BBC1: "I've thought about it but I think it's going to be very hard because Yohan, he's just come into the game and he's running pretty well, and I'm sure there's going to be a lot more cats coming up to run.

"I'm just happy. I'll take it a step at a time."

Asked whether he would run more often in Britain if tax laws change - a factor in him having stayed away in the past - Bolt said: "As soon as the law changes I'll be here all the time.

"I love being here, I have so many Jamaican fans here and it's wonderful."

States success

In the women's 4x400m relay, the United States stormed to a predictable and emphatic victory.

The quartet of DeeDee Trotter, Allyson Felix, Francena McCorory and Sanya Richards-Ross led from start to finish to beat Russia by almost three and a half seconds.

Jamaica claimed the bronze medal with Britain in fifth behind Ukraine.

Individual silver medallist Christine Ohuruogu was on the final leg for Britain but was left with too much to do by Shana Cox, Lee McConnell and hurdles specialist Perri Shakes-Drayton.

Ohuruogu said: "It would have been nice to come home for the medal, especially for the guys who didn't really perform how they watned to perform in their events, but it wasn't to be today.

"I knew it was going to be hard, I was trying to run and catch the Ukrainian, but in front of the Ukrainian was someone else so it was hard."

Shakes-Drayton, who just missed out on a place in the 400m hurdles final, added: "Today we would have loved to have got a medal, but it didn't go our way. But as a whole, as a team, we've done very well. We've run a season's best (3:24.76), that's the best we've ever run together.

"I had unfinished business to do considering what happened in my own event so I went out there and gave it all I could do."