Radcliffe makes her debut in style

At the halfway mark, the twice world half-marathon and world cross country champion was already an astonishing 83 seconds ahead of second-placed Kenyan Susan Chepkemei.

Radcliffe did not relent, and Russians Svetlana Zakharova and Lyudmila Petrova had to settle for a distant second and third.

The men's race proved to be a closer tussle with Khannouchi outlasting distance great Haile Gebrselassie and Paul Tergat in a tight contest.

The Moroccan-born American broke away in the final two miles to win in a time of 2:05:38, beating his previous world record by four seconds.

Khannouchi put on a record-breaking display

"I knew if the weather was good I could break the world record," he told the BBC.

But it was disappointment for Gebrselassie, who had set a blistering opening pace on his marathon debut.

He came in third behind old track rival Tergat, but still took some consolation that his time was the fastest ever for a marathon debutant.

Elsewhere, Britain's Tanni Grey-Thompson notched up her sixth victory in the women's wheelchair race in London, while compatriot Dave Weir won the men's race.