ALMOST half a minute sliced from the world marathon record in Berlin on Sunday has prompted renewed speculation at the prospect of the sub two-hour marathon being achieved.

Dennis Kimetto of Kenya lowered the record to 2hr 02min 57sec. That was 26 seconds quicker than the world best set just 12 months earlier by compatriot Wilson Kipsang on the same course, and conveniently sidelined confusion around the fastest marathon ever (2:03.02, in 2011), achieved on Boston's downhill course, and therefore ineligible for a world best.

Inevitably, Kimetto was asked following Sunday's win whether two hours was possible. "I am expecting a marathon in two hours," he said. "I can break this record again."

The runner-up, Emmanuel Mutai who was also inside the previous record, agreed. "The time is coming down and down. To beat two hours is possible. If not today, then tomorrow. Maybe next time we'll get 2:01."

Thirty years ago this month, Welshman Hugh Jones set the world best at 2:08.05 - still the UK record. Twenty years ago it was down to 2:06.50, held for six years by Somalian Belayneh Dinsamo. But six records in 11 years, improving by almost three minutes, marks an unprecedented assault, at an average of 24 seconds per race. At that pace, the two-hour barrier would fall some 12 years from now.

These successive world bests have all been in front of the Brandenburg Gate. Paul Tergat established the first of these (2:04.55) in 2003, a 43-second improvement on the year-old mark set in London.

That series has been fueled by the growth of commercial athletics, where huge sums have taken African endurance runners from poverty to a level of affluence mind-boggling by European standards, and the more this impacts, the sooner the record will fall.

The only surprise is that this climate of commericialism has not transferred with comparable impact on Kenyan female performances. Paula Radcliffe's world best of 2:15.25 has endured now for more than 11 years.

The 30-year-old Kimetto won marathons in Chicago and Tokyo last year, but made his debut only in 2012, in Berlin, with 2:04.15, fastest debutant ever. He was a subsistence farmer, growing maize and herding cattle in Kapngetuny, until 2008, and is a late developer.

One of seven siblings, he had to work the land and often could not afford to attend school. There was no radio or TV where he grew up, and he watched the Sydney Olympics on TV in his village community centre. He was inspired by the 10k duel between future marathon world record-holders Haile Gebrselassie and Tergat. "I thought, perhaps I could run at that level." Though he lacks their track pedigree, he has run faster than either of them.

For years, speculation abounded around the possibility of breaking four minutes for the mile, finally achieved 60 years ago by Roger Bannister. All manner of nonsense arose around the feat. It was physically impossible, potentially fatal, yet once achieved, the flood-gates opened. Sub-four-minute milers are now counted in thousands.

It took the perfect race, good weather, and reliable pace-makers (once judged illegal). A sub two-hour marathon will need all that, and more. A pan-flat course, like Berlin, for starters. Perfect weather, big financial incentives for both contenders and pace-makers, a hot field to provide the impetus for the final stages.

Kimetto now pays the school fees of his brothers and sisters, and the financial incentives to rise from poverty can't be underestimated. The £93,000 he collected on Sunday equated to some 230 years' income for a Rift Valley subsistence farmer. The comparable figure for a Brit would be some £4.5m.

The clue to when the two-hour marathon is possible may lie in times for the half marathon. The world best for the half is 58:23 (interestingly by a man with a best of just 2:10.41 for the marathon). Kimetto's fastest is 59.14, suggesting that a runner capable of 57 minutes might complete a marathon in two hours.

Sport fiction for now, perhaps, but Kimetto has just nudged that day significantly closer.

And another thing A belated valedictory salute to the Grand Old Lady of athletics, Dorothy Tyler, who died last week aged 94. The last surviving GB medallist from the 1936 Olympics, Tyler set a high jump world record of 1.66 metres in 1939 - it would still have been good enough to win Scottish championship medals in the past decade. Despite losing two Olympic Games in her prime to the Second World War, she twice won silver in four Olympic appearances. If current count-back rules had prevailed, she'd have been gold medallist at 16, in Berlin, where she recalled joining team-mates in chanting: "Heil King George" at the Hitler Youth.

After the war, part of which she spent driving trucks for the Dam Buster squadron, she returned as a mother of two in 1948 to win silver again. Empire Games champion in 1938 and 1950, she was still clearing 1.52m aged 46, in club matches, and went on to become Surrey over-80 golf champion. The feisty Tyler teased flopper Dick Fosbury at a 2008 lunch that he should have been disqualified for going over the bar head first, and then turned up for another London 2012 function with a plastic carrier bag full of 1936 memorabilia.

And finally

I was disappointed at Lizzie Armitstead's failure to claim a medal in the UCI word road race championships on Saturday. If the race had been honestly run, the British rider would almost certainly have done so, but the Dutch defending champion, Marianne Vos, decided not to co-operate in the final stages of the four-woman breakaway which included herself and Armitstead.

This would have been absolutely acceptable if it had been to help her team catch up, but it was to allow Pauline Ferrand-Prevot, a French member of Vos' commercial team, Rabobank, to get in touch within sight of the finish, and then win.

This is a clear conflict of interest, a tawdry display which diminishes the sport.