Live on TV: BBC Sunday, from 9.0 a.m:ATHLETICS/London Marathon: Through all the grand history of marathon running few races have been more anticipated than what comes in London tomorrow. Not just the most elite field ever assembled, but mostly because of one man: Haile Gebrselassie.

For a decade he's been known as the world's greatest distance runner. At home in Ethiopia they call him the "Emperor". Four world titles, twice Olympic gold, and breaker of 15 world records. Throughout those years the statisticians dreamed of what he would do over 26.2 miles.

Now comes the answer. Even without the 33,000-odd runners who will follow him around London tomorrow morning, people would still come out to watch. Debuts like this happen only once in a generation.

Yet when Gebrselassie walked into the Marathon Expo yesterday, an event in itself in London's docklands, he could have been just another of those 33,000 picking up his race number; a fragile, almost child-like figure, whose ordinariness has always set him apart in world athletics.

What differences, though. He's getting about £250,000 to show up and will double that if he breaks the world record of two hours, five minutes and 42 seconds. Other bonuses would follow, plus as much Adidas money as pumped to David Beckham.

Then he sits down for a quiet word with the Irish media, and the legend becomes truth. Gebrselassie confirms that reported training, those three-hour runs at altitude in Addis Ababa, and sure he feels capable of breaking the world record. "Well of course I have prepared well for this race," he smiles. "Now I'm just waiting to go but no athlete can say they will definitely win. What I can say is that I'm just one of the competitors, and the rest we'll wait and see. But I'm confident I'm ready to do something special.

"But the world record will depend on a lot of things. I want to reach halfway in 62:30, which won't be too bad for me. There will be pacemakers to help me up to there."

Word has spread that Gebrselassie actually has some marathon experience, once running the distance in Addis Ababa: "Yes, it's true. I was 15, and I ran 2:48. I remember it well."

Since then he has burned a hole in track world records, and is still fastest ever over 5,000 and 10,000 metres. For this longer race he has only made minor adjustments.

"No, there hasn't been any great difficulties in the marathon training. And there's no big difference training for the road. The big thing is training longer. Sometimes it goes to three hours."

He smiles wider still, as if recalling the intensity of those runs. He has averaged around 25 miles a day, once in the morning and again in the afternoon, always in Addis Ababa.

"Why anywhere else? There is no better place to train that Addis Ababa. It's my home, I'm there with my family, that's nice. And I can train with other Ethiopians, so that we can help each other."

Nor has he adjusted his diet. This, remember, is the man who has admitted his fondness for fast food. "What I eat before the race is not a big deal. But I only sometimes go for fast food now. Before I was going a lot more, but then I started to think more about other foods."

But he has changed his running technique: "Just a little bit. Before I would run all on my toes, but now I'm using more of the foot. It was a little change, but I didn't want to change too much. I still need my old style of running for the track."

It's clear he wants to achieve more on the track. He is, after all, still only 28: "Well I'm almost 29, next week actually. But I've always wanted to start my marathon in London. I heard it was the best course to start for someone like me. But I wanted to run against many big names because that's important for me."

This is certainly a race with big names: his old Kenyan rival Paul Tergat, the world record-holder Khalid Khannouchi of the US and defending champion Abdelkader El Mouaziz of Morocco. A mere sideshow, one suspects.

Like Paula Radcliffe's debut in the women's race.