Christine Ohuruogu won Britain's 16th gold medal of the Games in a surprise victory in the women's 400m at the Beijing Olympics.

The 24-year-old dropped to the floor in exhaustion as she became the first ever British woman to win the event.

She produced an electric finish to overtake the flagging favorite for the race. Sanya Richards from the United States clearly felt she had the race won going into the home strait.

Britain's Christine Ohuruogu crosses the finish line to win the women's 400m final at the National Stadium August 19 2008. [Agencies]

Ohuruogo had her measure, however, finishing in 49.62 sec with Shericka Williams of Jamaica taking silver in 49.69 and Richards a disappointing bronze in 49.93.

"You never think it's a reality, it's something you dream about. As I came across the line I thought 'oh my gosh' - I don't know what to say," Ohuruogu told the BBC.

Ohuruogu's victory means that Great Britain's Beijing performance is its best since Britain hosted the Games in 1908. It now has 16 gold and is third place in the medal rankings behind China on 43 and the United States on 25.

Ohuruogu's success comes a year after she completed a 12-month ban in 2006 for missing three out-of-competition drugs tests.

Born in Newham, East London, of Nigerian parents, she graduated in linguistics from the University of London in 2005.

As well as the Olympics and the world she also is the current Commonwealth champion.

Agencies