Let me be honest with you, because know me well enough to spot it if I'm not.

I do not run. I have never run. Two weeks ago, I couldn't have told you the difference between a fun run and a hostage situation, and I'm still not convinced there is one. And yet this October I'll be running the Royal Parks Half Marathon. That is 13.1 miles. On purpose. In public.

I'm "training," a word I'm using with enormous generosity, either in Ireland, where the rain takes it personally, or in Sri Lanka, where the heat does. Three runs a week, plus pilates, yoga and strength training, because it turns out you cannot simply decide to run 13 miles, you first have to become a slightly different person. I now own more Lycra than dignity. There is no version of this where I'm comfortable, no version where I'm enjoying myself, and not a single day where I haven't quietly regretted offering.

Now here's the bit where I'm meant to sell you the cause, and I should warn you I'm about as good at that as I am at running.

What Dogstar does is as gloriously unglamorous as my soggy Irish laps. We sterilise dogs and cats in Sri Lanka. One unsterilised female and her descendants become an entire street population in just a few short years. So sterilising one animal doesn't save one life. It quietly prevents thousands of lives of suffering that will now simply never happen.

In 19 years we've sterilised over 115,000 animals. It is genuinely brilliant, welfare-led work, and yes, as I type that, I'm aware it has roughly the fundraising sparkle of my tempo-run-to-easy-run ratio. Nobody ever cried at a photo of a litter that was never born. That's the whole problem with prevention: it works so well it becomes invisible. But hand on heart, it is the single most useful thing you can do for a street dog or cat.

So here's the deal. I'll spend the next 19 weeks running three times a week in weather that appears to hold a personal grudge against me. You donate. Anything at all towards my target of £2,000 will help our extraordinary veterinary teams do what they do best, and will help me regret my life choices very slightly less.

And if I hit the target, there will be photographic evidence of me crying in the rain. Consider it a stretch goal.

Thank you. Genuinely. Now I have to go and run, which I would like formally noted, I do not want to do.

Sam