Martin Lel is hoping to be declared fit today to defend his Flora London Marathon title and the Kenyan's presence on the start line could lead to the world record coming under attack from the event's best-ever gathering of elite long-distance runners.

Lel had an MRI scan on a hip complaint late last night and the early indications were that it is not serious.

That is good news for race director David Bedford. He will now be able to boast that the men's marathon will feature reigning Olympic champion Sammy Wanjiru and another four of the first six runners home in Beijing last year. There are also the first four from the 2008 London epic, world marathon champion Luke Kibet, Zersenay Tadese - who has held world titles at 20km road running, cross-country and half-marathon - and six of the top 14 quickest men of all time.

The target is the world best mark of 2hrs 3mins 59secs set by Ethiopian legend Haile Gebrselassie in Berlin seven months ago. And Wanjiru, for one, is up for the challenge. "If the pace is very good on Sunday, I'll try to break the world record," he said. The 22-year-old's fellow Kenyans Elijah Kitani and John Kales are the designated pacemakers who will be instructed to keep to a world record schedule for the first 20 miles. They are likely to have lots of company as last April seven runners were on world record pace until the 21st mile.

It was lanky Lel who produced the strongest kick to take his third London title in a course record 2hrs 5mins 15secs, just nine seconds ahead of Wanjiru. The 30-year-old is now going for an unprecedented fourth win around the streets of the capital and claimed: "London has the cream. It can invite the strongest runners from all over the world and you know that if you win you are the champion of champions."

Wanjiru would dispute that claim, given the manner in which he survived the searing heat of Beijing to become Kenya's first Olympic marathon champion in a staggering 2hrs 6mins 32secs, obliterating the Games record.

In the absence of Gebrselassie, who dislikes the London course, the duel between Lel, if he is fit, and Wanjiru will be a feature of Sunday's race. Lel said: "I will be under pressure but pressure is actually good for me. I'm ready to go with the pace, especially if my friend Wanjiru tries something."

But it is not just his "friend" that Lel must worry about. Olympic bronze medalist Tsegaye Kebede is looking to score Ethiopia's second major marathon triumph in the space of six days, citing compatriot Deriba Merga's victory in Boston on Monday as "an inspiration to do well in London".

Eritrea's Tadese, who likes to run in the red and white colours of his beloved Arsenal, could spring a surprise on his debut over the full marathon distance. Abderrahim Goumri was second to Lel on his own marathon debut in London two years ago and the Moroccan will be looking to go one better this weekend.

Romania's Olympic champion Constantina Dita and defending London title holder Irina Mikitenko, of Germany, are among eight women in Sunday's field who have run personal bests in under 2hrs 22mins.

For home supporters it is a pity that Paula Radcliffe is absent with a toe injury. Pregnancies also keep fellow Olympian Liz Yelling and 10,000m international Jo Pavey out of the race. But Mara Yamauchi, sixth in Beijing, comes with form having retained her Tokyo 10km title and taking victory in the Matsue half-marathon this year.

British men's No1, Dan Robinson, chose to withdraw after suffering a series of colds brought on by an under-active thyroid. Robinson, 24th in Beijing, said: "It could affect me by one or two per cent and over 26 miles that can make a big difference."

That leaves Britain's challenge in the men's race to be led by Tomas Abyu, the Ethiopian-born runner who was granted citizenship in 2000.

Top five men and women in contention to win the elite race

The men...

Martin Lel (Kenya, 30) The defending champion and course record holder is going for an unprecedented fourth title and a third win in a row. But he has been troubled by a hip injury.

Sammy Wanjiru (Kenya, 22, left): In Beijing, became the first Kenyan athlete to claim an Olympic marathon title. Runner-up in London last year.

Abderrahim Goumri (Morocco, 32): The nearly-man of marathon running. Finished three seconds behind victorious Lel in London in 2007, was third here last year, and has twice been second in New York.

Tsegaye Kebede (Ethiopia, 22): Bronze medallist in Beijing. Second fastest Ethiopian behind Haile Gebrselassie.

Felix Limo (Kenya, 28): Time of 2hrs 6mins 42secs at Rotterdam in 2003 was second fastest debut ever. Beat Lel to London title by two seconds in 2006.

The women...

Irina Mikitenko (Germany, 36,): Formerly competed for Kazakhstan but acquired German nationality in 1996. Staged late break last year to win in London, but missed the Olympics through lack of fitness.

Constantina Dita (Romania, 38): London veteran with seven appearances, was runner-up in 2005. Aggressive style and surprise Beijing gold medallist.

Catherine Ndereba (Kenya, 36): Most consistent woman, with two world titles, a world silver, two Olympic silvers and a world record. Second in 2003.

Zhou Chunxiu (China, 30): Said to run 180 miles a week in training. It paid off in Beijing where the 2007 London champion took bronze.

Berhane Adere (Ethiopia, 35): Took world titles indoors at 3,000m and outdoors at 10,000m before turning to marathons. Twice winner in Chicago and last year ran away from the field to claim the Dubai race.