BBC SPORT | Athletics | Ohuruogu claims gold for Britain

Fellow Briton Nicola Sanders won silver while Jamaican Novlene Williams, who led for most of the race, came third.

Ohuruogu, whose one-year ban for missing three out-of-competition tests expired earlier this month, looked out of contention on the back straight.

"It will probably sink in later," said Ohuruogu, whose time is a new personal best. "For me I won a race - the fact that it is the worlds will sink in later.

"It was very tough, but I'm very proud of myself because I worked hard and I had an operation on both legs which was hard enough.

"Every single day I did my work - not always sure what I was working for but I always had the Worlds in mind. It was a dream. I hoped I would and now I've done it."

Williams was leading going into the final straight but as she started to slow, Ohuruogu and Sanders managed to find the extra pace to sneak ahead in the closing strides.

Ohuruogu is the first British woman to win a World Championship track event since Sally Gunnell's 400m hurdles gold in Stuttgart in 1993.

OHURUOGU FACTFILE

2004: Part of 4x400m relay squad that comes fourth at the Athens Olympics

2006: Wins 400m Commonwealth gold in Melbourne

2006: Banned for 12 months after missing three out-of-competition drugs tests in the last 18 months

2007: Returns to competition, winning the 200m at the Scottish Championships

2007: Wins 400m World Championships final in Osaka

The one-two is Britain's first since Colin Jackson and Tony Jarrett secured the top-two places in the 110m hurdles in 1993.

"I am a bit bewildered at the moment," said Sanders. "I let them get a bit too far away on the first 200m.

"We had a lot of work to do. The technique went out of the window and I just dived for the line.

"I had to have tunnel vision and concentrate on my own race. At the beginning of the year it didn't look like either of us would be here but now we have a one-two. It's fantastic."

Ohuruogu, who was running in only her fifth race since her suspension expired, is still waiting to find out if she will be able to challenge for the Olympic title in Beijing next year.

The British Olympic Association automatically gives life bans to athletes who have committed doping offences.

However, Ohuruogu has appealed and her chances of success were boosted when the BOA recently cleared triathlon world champion Tim Don and judo player Peter Cousins, who both missed three drugs tests.