As I spend much more of my time behind a music or computer keyboard than I do pounding the streets of Hertfordshire, I fear even a half-marathon may be a non-trivial thing to do. Still, there's nothing more pitiful, and hence donation friendly, than a middle-aged composer trudging up and down what I believe to be a particularly hilly course, in aid of an amazing charity.

Let's face it - it's going to hurt. So even if you're not in the small group of  people who've enjoyed my tunes over the years, and you're in the vastly larger group who would quite like to see me suffer a reasonable amount of non-fatal discomfort - now's your chance to participate.

Donate some money. Even a tiny amount. Unless you're one of my loaded media friends who moan on about the costs of running your second homes. You buggers can dig deep. It's the only way you're not going straight to hell.

And if you're a Sherlock fan, and donate, I'll sign pretty much anything for you - blank cheques, divorce papers, Downton Abbey soundtrack CDs ...