I've run it twice before in the nineties. In terms of personal satisfaction, the first time I ran was the single most significant achievement of my life. I set my own personal goal, didn't care about what anyone else was doing, and worked for months to achieve it. To those of you who detest most TV sports commentary, as I do, I'm afraid that all the cliches that messrs Cram and Foster trot out every year are in fact true: the fun runners setting their own targets, the money raised for chairty, the bonhomie out on the course and the way the cheers seem to physically lift you just when you are flagging. And if I can do it, anyone can - I started jogging in my late 30s because I was unfit and overweight, and gradually just kept going. In the words of the immortal yosser hughes, I can do that....and I did.
And that idea, of setting and achieving personal targets, has been very important for me ever since, in work and life I mean, not running.