Yesterday, I found myself standing on top of Ben Nevis. A few months ago, I wouldn't have thought it possible. I was a heavy smoker who got out of breath walking up a flight of stairs.
Having quit smoking and graduated C25K, I made it to the top of Britain's highest mountain.
I felt a great sense of achievement when I graduated but yesterday I remembered why I wanted to do the programme in the first place.
It's not just an end in itself but makes you fit for other challenges in life.
What a wonderful feeling.
That's me on the left in the picture, quite early in the climb. On the right is my friend Ellen, a lifelong hillwalker whose family's "just one more step" mantra helped me to the top.