I'm taking on over 6 marathons-worth of walking in 10 consecutive days around Great Britain this April to help children beat blood cancer.

Since my first walk in 1985 the survival rates for the most common form of childhood leukaemia have risen from 20% to over 90%. And that’s thanks to people like you fundraising for research.

It’s the people on the walk; the patients, the families, the ordinary people who want to do something extraordinary, who have raised £13million with me since I began walking. Every step that you take is a step closer to beating childhood blood cancer.

It was back in 1977 when I was in hospital with a foot injury, that I met a group of children with leukaemia. They all looked so normal and I was horrified to hear that none of them were expected to survive. It was then that I vowed to do something to help.

Since I began walking, huge progress has been made, but we need to keep improving treatments to give every child the chance to live a normal healthy life.

We’ve still got a way to go. I won’t hang up my trainers until we have beaten childhood blood cancer but I need your support.

Sir Ian Botham