I was never built to be a runner.  Definitely.  So I thought to myself - what's the thing that's going to test you, to really push you beyond your limits?  Well, I've been a Londoner for over a decade now, and after 10 years of watching those poor people pound 26.2 miles around London on a drizzly Sunday morning, I found the answer - the London Marathon.

Now some of you know that I've done some silly things in my time, climbing a few mountains, cycling across a few countries, even battling the Artic Circle on husky dogs or limiting my reproductive potential by horse riding across Mongolia, in a Mongolian saddle.  But I've never actually raised money for charity.

And now I've found one.  It's the Juvenile Diabetes Research Foundation.  Have a look at www.jdrf.org.uk if you like.  This is one of the best charities I know.  It has put 30 years of hard work into finding a cure for Type 1 Diabetes, the type that affects young people.

In my days as a doctor, I've seen enough of these kids - blind, needing kidney transplants, multiple amputations, all in their 30s as they've been ravaged by Type 1 Diabetes.  A cure is on its way, but desperately needs more funding.

So, if you don't want to do it just to see me struggle around 40kms of tarmac, do it to help the charity.  But do it.  Donate. 

Thanks.