This week I will be undertaking one of the maddest things I have ever done. At the ripe old age of 55 I have decided to do my first marathon.
I have always been a runner. Some of you will have seen media shots of my coming back from my morning run (which always seem to coincide with Conservative leadership contests).
But my idea of a run is a gentle three or four mile jog with the dog with no other runners and not a stopwatch in sight.
This time it is 26 miles, everyone wanting to know if I will do it in less than four hours and 50,000 other runners. Why the foolhardiness of doing the London Marathon?
I was actually asked to run it by my brother who is bravely battling cancer at the moment – and am thrilled that he is able to run it in the middle of his treatment.
He has always been infinitely more sporty and energetic than me and has already done two marathons before.
He has also helped me with the training, which essentially seems to involve building up to distances of about 20 miles about a month before the big day and then winding down gradually.
In order to meet that strenuous programme we have been running in the Surrey Hills around Hascombe and Hambledon and along the River Wey between Godalming and Woking.
Our stunning local countryside was, it has to said, brilliant at distracting me from the agonies and tortures of ridiculously long runs.
Whether it is the vista from the Greensand Way, the bucolic pastures around the Wey or the extraordinary views from Hascombe Hill, I felt my energy return.
It won’t surprise you to hear also found myself doubly determined to stop sewage being pumped into our rivers, secure National Park status for the Surrey Hills and deal with the curse of litter.
But the biggest connection between my running and local campaigning is that every penny I raise will go towards the new Cancer and Surgical Innovation Centre we are trying to get built at the Royal Surrey.
So far a whopping £25 million has been secured from the NHS and £180,000 from local fundraising - so a massive thank you to those who have contributed.
Many generous donors came to an event at the Royal Surrey last week at which we learned just how cutting edge the new centre will be, not least with robots performing much of the surgery, so it really is going to transform cancer care locally.
When it comes to the London Marathon, my Just Giving page has raised about £14,000 so far – but if you think you could help top it up, for a wonderful cause, please go to www.justgiving.com/fundraising/thehuntbrothers
And watch your TV screens around 4pm on Sunday when I expect to be crawling over the finish line!