How to run a stylish marathon

Now not a lot of people know this, but marathon training is a doddle. Believe me, the running is easy. You simply put one foot in front of the other over and over again for a very long time until you get bored. Even I can do that.

No, the real challenge for a Mayfair belle like me is how to stay the style course during those months of tiresome pounding on the streets of London when all you've got for company is your mini-disc. And as anyone knows, style is a serious subject.

Forget about tear and focus on wear, beauty tips and after-care. And then there is the support team - I mean those people you just have to consult about twinges and binges, stitches and cramps and chocolate cravings throughout the whole gruelling ordeal.

My golden rule has been to throw out common sense in favour of street cred, to have zero tolerance for words like sweaty, sticky and blotchy and to think only cool, svelte, sexy and lissome. Let's get down to kit. My temple of style in London is The King's Road Sporting Club, where manager and marathon runner Anne Bartlett spent serious time sorting out my gear.

Nike Dri-FIT is fantastic for keeping you, well, dry, of course, and Supplex does a slinky, scanty range of bra tops and dinky shorts. Then Anne handed me a bullet-proof vest. At least that's what I thought it was. But no, it was merely weighted, for endurance training. In the Bronx, perhaps, but not in Mayfair, surely? The seriously sexy item, though, was a black foam Tune Belt for carrying your mini-disc, glucose tablets and power bar.

I spoke to Ed Powell, my trainer at the very chic Harbour Club, about shoes. Gucci does no running accessories, so I wanted Ed's take on the new crocodile Quick trainers at Hermès, a snip at £2,800. He stifled a laugh and sent me straight to Run and Become. Be warned, this is no style emporium; they care purely about fit and how you actually run in your shoes.

My beauty guru, Eve Lom, told me I was stressed. Stressed! Of course I'm stressed! Ed's told me to cut out Pol Roger and drink mineral water. Peering at my skin, Eve pointed out that the first thing I must do, on getting home from a 12-mile circuit, was not stretching but scrupulously thorough cleansing, before the sweat and pollution settled into my every pore. And I should apply her lip emollient before I set off into the freezing elements, not just when I got back.

I supplemented that advice with Shu Uemura Regenerate face cream and Tova's Cactine Eye Mask, both ideal for coping with the harsh elements. I'm getting through gallons of Vaseline, too; it's essential for the lips, under-arms and inner thighs (to prevent chafing, darling, you must know that).

Meanwhile, Nigel Tewkesbury, foot man to the stars, peered at my toe nails. It would help if I cut them from time to time, he mused. But this was nothing to David Propert, without doubt the most stylish osteopath in London. He said I had wobbly knees and all this running malarkey was, frankly, taking its toll. He gave me strengthening exercises which he promised could only enhance my street cred in the gym.

So back to Ed Powell. He has been a pain. From day one he insisted on a sensible high-carbohydrate diet, a proper training programme, and has remained impervious to my mewling about my unstylish trainers. On a Thursday evening, instead of visiting 23 Romilly Street (a club sort of club, not an exercise club), for a glass of fizz or three, I am now subjected to doing interval training at Battersea Park.

When despondency strikes and I am buffeted by howling winds and driving rain as I slog across the Royal Parks and back to the office via Old Bond Street (the nearest I get to Prada these days is window shopping as I schlep by) I remind myself that I am doing this for overseas-aid charity the Scientific Exploration Society, and that a beleaguered tribe of remote American Indians will have cause to raise their beakers of sugar cane to me one day when the sponsorship money rolls in. And I remember poor old Pheidippides, Greek Olympic champion and instigator of the marathon (although he never knew it), who, in 490BC, ran from Marathon to Athens, about 22 miles, only to drop dead on arrival. Whether he was wearing the equivalent of Nike Dri-FIT at the time, we'll never know, but I guess at the end of the day, reaching that finishing line and being able to live to tell the tale will surely be a style statement in itself.

A Grand Adventure, a documentary about the Wai Wai, featuring Anna Nicholas, will be shown on BBC2 as part of the Mission series at 9pm on 12 April. To make a donation to the Wai Wai, call 020 7629 8118.