Martin Lel (top left) leads an invasion of Kenyan talent on the streets of London
If you want proof of how the balance of power in long distance running has shifted, compare the lists of top marathon times in 1981 with those of 2008.
Kenya's men are stronger in depth in the marathon than any other country in a single discipline in athletics
In the year of the first London Marathon, not one Kenyan athlete was among the world's top 100 marathon runners.
Now their men have a majority share in the rankings and will surely be dominant again in London on Sunday.
Martin Lel is again the favourite after winning in London for the third time last year in an event record two hours five minutes and 15 seconds.
Kenya's men are stronger in depth in the marathon than any other country in a single discipline in athletics, or indeed in any world sport.
They filled 65 places in the world's top 100 last year and in Frankfurt last October, the first 14 were all from the East African country.
It is not only city marathons where Kenya are supreme - Samuel Wanjiru became Kenya's first Olympic champion in Beijing, while Luke Kibet is the reigning world champion.
No Kenyan woman has won an Olympic marathon title, but Catherine Ndereba has won two world titles and two Olympic silvers. She is the most decorated woman marathon runner in history.
All three of these stars are due to be in action on Sunday and you can never discount any Kenyan who appears on a distance running start list.
In 2003 when Paul Tergat produced the first sub-2:05 run, he was pushed all the way by his compatriot Sammy Korir, who finished only one second behind.
We all knew Tergat's pedigree, but Korir's breakthrough - from 2:08:02 six years earlier down to 2:04:56 - was a shock.
Something similar happened on 5 April in Rotterdam when Tergat's Commonwealth record was unexpectedly broken with 2:04:27 by two of his compatriots, with a third moving to sixth on the world all-time list.
On the very same day in Paris, a record 11 men broke the 2:09 barrier.
Eight of them were from Kenya yet it is quite possible that none will have done enough to be selected to represent their country at the World Championships.
The key to the explosion of Kenyan success appears to have been down to the input of foreign agents, coaches and administrators, along with greater organisation in Africa.
And yet Europe and certainly Britain have seen their own standards diminish as Kenya's have risen.
In 2003, Paula Radcliffe's world record was the fastest marathon by any Briton, male or female.
More than 100 British men ran faster than 2:20 in 1983. Twenty-five years later that total has dropped to just eight with none so far in 2009.
We may well see a British Wimbledon champion or even a World Cup winning football team before we see another British male runner win the London Marathon
Dan Robinson has achieved credible runs in recent years but the base of the pyramid of talent is shrinking and ageing.
All of our top 10 men in 2008 were either in their 30s or will be by the end of 2009.
In Kenya, the opposite is true. Wanjiru had already set a world half marathon record as a junior and in Beijing became, at 21, the youngest Olympic Marathon Champion since 1932.
I fear that we may well see a British Wimbledon champion or even a World Cup winning football team before we see another British male runner win the London Marathon.
But there will be plenty to cheer on Sunday.
First, Britain's Mara Yamauchi is still improving following her sixth place in Beijing and will certainly make her presence felt in the women's race.
Second, our Paralympic heroes David Weir and Shelly Woods will be tough to beat in the wheelchair section.
And thirdly, this wonderfully organised event will once again be the perfect showcase for the best in the world.
Many of the statistics cited in this article were compiled by the Association of Road Racing Statisticians.