This confirms my impression from reading Paula Radcliffe’s autobiography My Story So Far. In every photograph, bar the shot of her crushed and weeping on an Athens pavement too exhausted to complete last summer’s Olympic marathon, her face radiates a smile so wide-eyed and rapturous she looks like a saint having an unusually ecstatic vision.

Gary Louth, however, her husband and some time trainer-manager, glowers from every page, eyes narrowed with malevolence. There’s the famous trackside shot from the 2001 World Championships in Edmonton of Gary bollocking Paula for only finishing fourth in the 10,000 metres. Even in their wedding photo, he can barely crack a smile.

And sure enough when we turn up at the offices of Paula’s physiotherapist in Limerick high street, a scowling Gary grills us curtly on the pavement. "Have you brought stuff for her to wear?" he asks the chap from Nike (Radcliffe’s sponsor, whose new shoe, Free, is a key component of Paula’s training regime). And while all Limerick gawps, Gary fingers through teeny Paula-sized sports bras and running shorts. "I like the red," he says frowning under his baseball cap. "Let’s lose the black."

Finally satisfied, Gary allows us into the clinic run by Gerard Hartmann, the world-renowned physio who has revived the damaged bodies of, among others, Kelly Holmes and Colin Jackson. In her book, Paula recounts recovering here from grievous injuries; I’d expected a luxurious rural spa, not a cramped former jeweller’s shop with a gym in its dank basement. But it is here, living above the clinic in a bedroom with a kitchenette, that Radcliffe will prepare for the London Marathon which, as we meet, is two weeks away.

"Paula’s in the bath," says Gary. By which he means Radcliffe has just taken a bucket across the road to Tesco where the nice guy on the fish counter has filled it with ice. Soaking her body for 12 minutes at arctic temperatures will help her muscles recover from her 22-mile morning run. In the afternoon, she may have a treatment session with Gerard in which he will push the point of his elbow into her thigh muscles so hard he makes her cry. Such is the glamorous movie-star life of the fastest woman ever to run a marathon.

As we wait, I attempt small talk with Gary. His flinty face, with its low brow and striking Slavic cheekbones, makes him appear furious in repose. But speaking about Paula his blue eyes widen and soften. He isn’t so much fierce as edgy and brittle, a shy, self-conscious person forced into an awkward public role. He is also unexpectedly frank. I mention Paula’s book. "I haven’t read it," he says. Your own wife’s autobiography! "I’m, well, a bit of a control freak, and I wouldn’t agree with little details of it. So I couldn’t bear to."

How is she running at the moment? (The previous weekend Paula had finished second at a 10K in New Orleans, 18 seconds behind Kenya’s Isabella Ochichi.) "Well, her legs were a bit flat, because it was the wrong time of her women’s cycle," he says, finding nothing untoward about discussing his wife’s menstrual cycle with a stranger.

But from her book, a personal pathology as much as a life story, I am already intimate with Paula’s body: her fallen arch, asthmatic lungs, the swollen glands in her groin, the space between her vasus medialis muscle and femur bone where doctors scraped away a pesky haematoma, her blood chemistry which makes her prone to hypoglycaemia, how when she is running hard her eyes roll back in her head to blank out pain.

Even the colour of the bowel movement she passed in her running shorts during that fateful Greek marathon – white from her undigested porridge – because anti-inflammatory drugs for her leg had upset her sensitive gut.

And the first impression of Paula is fragility. At 5ft 7in she weighs only 8st 4lb and carries 11 per cent body fat (the female average is 20-25 per cent). She walks gawkily, like a new-born creature. Her manner, too, seems delicate – sweetly solicitous yet so nervy that her whole body and girlish voice perpetually vibrate.

At a café opposite Gerard’s, Paula eats goat’s cheese salad with roast potatoes. "At the moment, it’s no wheat, no dairy, no gluten, no coffee, no tomatoes, no grapes. I went to see a naturopath and she held all these rods over food to decide what I could eat, which I thought a bit weird. Gary laughs at me. He says, ‘Oh my God, you’re eating "runner-freak" food.’ But it’s really improved my irritable bowel."

After Athens, Radcliffe feared she had done permanent damage to her digestive tract. It plays up, particularly before her period, vital nutrients and energy just seeping away. She used the Pill to shift her period before a race, but that made it worse.

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