SO HERE it is – the final one! After months of training I am at last coming to the end of what, if I am honest, has been a really gruelling (and probably slightly insane) challenge.

Running one marathon on it’s own is daft enough, two in two weeks is probably quite stupid but three in five weeks is definitely one too many… especially when the third is a power walk for which I have done no training whatsoever.

I am still trying to get my head around walking 26.2 miles when I know I could run it, but the rule book for the London MoonWalk - which kicks off in Hyde Park at midnight on Saturday (April 15) - dictates that one foot remains on the ground at all times.

Easy, I hear you say. How difficult can it be to walk a marathon distance when you have already run it? Actually quite difficult, trust me I know, after trying to keep up with my sister while we were on a five mile power walk early in her training for the same event.

The dynamics for power walking, or walking of any kind, are significantly different to running and anyone who thinks the moonwalkers are half-baked marathoners should think again. The level of commitment required to train to power walk a marathon is far, far greater – in time alone it’s a mammoth undertaking.

But that said, it is a bit like joining Monty Python's Ministry of Silly Walks and there’s the rub as far as I am concerned. Pride and vanity has stopped me from training for this event for fear of not being able to carry off the look, and I am sure this fact will come back to, um, bite me on the ‘you know what’ on Saturday night/Sunday morning. Still, on the plus side, if that happens at least it will take my mind off the fact that I am parading through the streets of London very much in my sister’s wake, sporting little more on top than a lurid bra covered in coloured crystals and ribbon tassels just as all the clubs and pubs are turning out, whilst quite frankly looking like I’m chewing a toffee with my butt!