Christine Ohuruogu produced an astonishing late charge while defending champion Amantle Montsho committed racing suicide, allowing the Briton to win the world 400m gold by four thousandths of a second on Monday.

Ohuruogu, the former Olympic champion, is famed for her storming finishes but even she looked out of it as Botswana's Montsho entered the final 30 meters with a big lead.

But Ohuruogu somehow closed the gap and timed her dip to perfection as Montsho crossed the line entirely vertical, having failed miserably to follow the advice given to all athletes from the day they begin competing.