Kenyan stars set to steal the spotlight in London

London (AFP) - Kenya's finest runners aim to restore their country's tarnished reputation when they battle for supremacy in the London marathon on Sunday.

More than 40 Kenyan athletes have tested positive for banned substances over the past five years and the east African nation's government moved to avoid a potential ban from the Rio Olympics by passing a new law earlier this week to make doping a criminal offence.

With athletics already in turmoil after the recent Russian doping scandals, the sport could do with an uplifting story or two and this weekend's race in the British capital should provide suitably diverting drama.

Kenya boasts the three quickest runners in the men's elite race in Dennis Kimetto, Wilson Kipsang and last year's winner Eliud Kipchoge, while the two quickest women, Mary Keitany and Gladys Cherono, both hail from the country.

None of that group have been implicated in any of the doping controversies and former marathon world record holder Kipsang this week launched a vigorous defence of his country's athletes ahead of what he hopes are more positive headlines after the 26.2 mile (42.2km) race.

"Sport is not special, it's just like life," Kipsang told the Daily Telegraph.

"You find that in society there are one or two criminals, but it doesn't mean the whole society are criminals.

"It doesn't mean all athletes or the whole sport is cheating. All these guys, we have been tested like seven or eight times, in and out of competition, and we should trust the results.

"Once the results come through and these guys are clean then the whole world should know they are clean.

"We, as the athletes, want to send out the message to the whole world, 'Please let us not try to sum up and say all Kenyan athletes are cheating'. No. We are clean."

Kipchoge is bidding to become the first man to retain the London Marathon title in almost a decade, but he will face a strong challenge from world-record holder Kimetto, who is back to form after a knee injury.

New York marathon winner Stanley Biwott, also from Kenya, and world champion Ghirmay Ghebreslassie of Eritrea could also pose a threat.

Ethiopia's Kenenisa Bekele should also be in contention as he continues to improve following a serious Achilles problem.

In the women's event, two-time winner Keitany is seen as a potential winner as she returns to the form of 2012 when she broke the national record in London.

Her challenges are likely to come from compatriots Cherono, Florence Kiplagat and Aselefch Mergia, with last year's winner Tigist Tufa heading up the Ethiopian contingent.

"I was very surprised by my victory last year," Tufa said. "I want to win again and I did a lot to prepare myself for this race."