On October 2, I will be running my second London Marathon. It's 22 years since my first, a wonderful yet painful four-and-a-bit hours that have taken a couple of decades to get over. But now it's time for another go - older, possibly wiser and aiming to beat my previous time. 

I am raising money for Cancer Research and will be running in memory of my Dad, who was by the side of the road near the end of my 2000 London Marathon and, having seen the state of me then, would probably think I am quite mad to come back for more. He may be right.