"I'm 60. If I've got my figures right, I'll live at least 20 years, so I believe in the next 20 years we will see the first sub two-hour marathon," London Marat

"I'm 60. If I've got my figures right, I'll live at least 20 years, so I believe in the next 20 years we will see the first sub two-hour marathon," London Marathon race director Dave Bedford says. Wishful thinking? How does his lifespan affect the probability of the 2-hour mark being broken?