A week ago, I lost my dear friend, Sandra, to stage four breast cancer, which had moved to her bones and liver.

Our friendship was one which spanned our entire adult lives. I first met Sandra, aged 18, when we were selected to live and work in Cairo with the Project Trust. And the last time I saw her was when she visited me in Cambridge just three weeks before her death. In the intervening years, we shared a special friendship.

In honour of that friendship - and in memory of a brave and wonderful woman - I would like to raise as much money as I can for Macmillan Cancer Support. The money raised will enable the charity to provide vital cancer services, fund research, support the cancer workforce, and campaign for better cancer care.

Sandra and I talked a lot in her last months about health, and about making the most of life, and so I feel that it would be appropriate to raise money by doing something which will also benefit my health. To that end, I pledge to get in my target 10,000 steps every day - at least for the next year and, ideally, from hereon in.

Donating through JustGiving is simple, fast and secure. Your details are safe and, once you donate, they'll send your money directly to the charity.

Please donate, if you can, and help support the fight against this pernicious disease.