Cyclists of John's age are not so unusual. Cyclists of John's age who are as good as John certainly are. And cyclists of John's age who are as good as he is AND have prostate cancer are extraordinary.

A very decent club rider in his youth, John didn't cycle from his mid-20s to his mid-60s. But it's clear that the talent was just lying dormant, and having taken up the sport again in retirement he set himself the target of riding the Marmotte to mark turning 70. Then came his diagnosis.

A lot of people on discovering they had prostate cancer would have given up any thought of attempting something as crazy as the Marmotte. But not John. He simply brought the target forward. It was also an opportunity to raise money for the leading cancer hospital the Royal Marsden, where John was being treated.

John was so positive on that audax ride - chivvying everyone along - that I never doubted he had the mentality to conquer the Marmotte. He had been training hard all year - much harder than I had for the Etape - but it was still a massive physical challenge.

The Marmotte took place earlier this month - the same weekend as the Etape, as it happens - but rather than me tell you how John got on, check it out for yourself at John's Challenge, where John has kept a blog detailing his progess towards the ride and what happened on the day. It's a fantastic story, and when you've read it I hope you'll support his cause. Last week he was up to £4,500 in sponsorship, and he wants to hit £5,000. It would be great if Cyclotherapy readers were able to add their names to his list of donors.

Good luck, John, and thanks for the tow. I might not have made it round the Etape without it.