The London Marathon yesterday revealed the men's field for next April's race. Martin Lel (best, 2:06.14) will defend the title, one of 12 men in next year's Flora field to have run under 2hr 10min. He also won New York last month, first man to win both races in the same year.

Former world record-holder Paul Tergat (2:04:55) is fastest in the London line-up, one of five men to have gone under 2:07, while another four have broken 2:08.

It's one of the strongest fields ever.

Race director Dave Bedford has others on his shopping list, but is coy about naming them. They're likely to include Haile Gebrselassie, who lopped 19 seconds from Tergat's world mark in Berlin this year, and Sammy Wanjiru, who lowered the world best for the half distance to 58:33 last March.

Bedford is unlikely to be able to move on Geb until he sees how the Ethiopian recovers from the Dubai Marathon on January 18. It carries a first prize of $250,000 and a $1m bonus for a world best. "There's also the issue of whether Haile would want to do another marathon in April, with the Olympic Marathon coming up in Beijing," said Bedford.

Only 14 Brits (two Scots) have ever broken 2:10 and only two in the past six years. The UK and Scottish records are more than 22 years old, but worldwide standards, driven by vast rewards, run ever higher. It is surely still a few years off, but the two-hour barrier is now under threat. Bedford and I concurred yesterday in the belief that the record will be 2:02 by 2015. "I hope to see two hours broken. Without doubt that will happen by 2030," he predicts.

Jos Hermens, the Dutchman who manages Gebrselassie and his successor as holder of the world 10k record, Kenenisa Bekele, said: "I believe Haile is capable of 2:03 in the near future. He has the ability. I think Kenenisa will eventually run low 2:02, or maybe just under. But under two hours?

"Definitely, in Africa, the talent is there, and with improvements in training, medical care, and food, there's quite a bit of room for improvement. But as living standards in Africa rise, perhaps the motivation is less, like in Europe."

Significant improvement on "good" records is not unusual. When Paula Radcliffe set the current women's best of 2:15.25, she took almost two minutes off her own world mark. Joan Benoit's world best in 1983, was an improvement of 2:46. "So you could easily see 2:02 for the men's marathon by 2015," argues Bedford.

However, major change on current times may have to wait for the next generation of 10k runners.

Bedford reckons Bekele, who relieved Gebrselassie of the world 5000 and 10,000m records, will step up in the foreseeable future. "In the same way as Haile and Paul made a significant step after moving from 10,000 to the marathon each was world 10k record-holder I think we may see that again, and we will get significantly closer to two hours."

Eritrean Zersenay Tadese, who beat Bekele for world cross-country gold this year, may help push up standards if they both move to the marathon and replicate their rivalry.

Past 10,000m form is often thought a better gauge of marathon potential than that over the half marathon. But of the top 10 fastest marathoners, only Geb and Tergat are in the top 10 at both (or either) of the other distances. The jury remains out on Sammy Wanjiru, world half marathon record holder at 58:33. He won on his marathon debut in Japan last month in 2:06.39.

There will doubtless be numerous quaint elixirs offered to explain success. The Chinese boasted of a cocktail of caterpillar fungus and turtles' blood, the Japanese swear by amino acids extracted from hornets, and the greatest of the Flying Finns was alleged to be fuelled by reindeer blood. When Radcliffe broke the record in London, in 2003 (and ran faster than any GB male all that year) she spoke of an unguent of emu oil, an Australian Aboriginal medicine which had helped her recover from having been whacked by a bike while training.

More than any secret balm, however, the most essential item is old-fashioned sweat. "From a British viewpoint, I think every single time it comes down to not being prepared to do enough work, said Bedford.

"I think that's the only reason."

Of the world all-time top 45 in the marathon, 37 are African-born. At 10k all 45 are African, and at the half, it's 41 out of 45.