The motives of the sources who have told the investigative journalist Michael Crick that Mrs Duncan Smith did not deserve the salary she was paid for being her husband's diary secretary in the first 15 months of his leadership are open to speculation. Among the many resentments seething around Iain Duncan Smith and his wife, is enormous huffiness about how Betsy won't play ball, and offer herself up as a picturesque asset.Betsy, far from being on hand to support her husband, moved the family home away from London not long after he became leader, and persuaded him that he should come to work late on a Monday morning so he could spend time with his family.She is known to be visibly irritated when private time is interrupted by politics, advises her husband against taking advice to be glitzier ("It's just not Iain," she says), and is considered by some to be nothing but a disappointing encumbrance when she so easily could be a vote-winner.Indeed, it may be this kind of bad feeling that has contributed to Betsy Duncan Smith's predicament. Mrs Duncan Smith's clothing arrangements were duly declared in the register of MPs' interests, and no doubt those keen to exploit Mrs Duncan Smith's photogenic appeal assumed they were on to a good thing.The idea, presumably, was that with careful handling, Betsy would have warmed to the idea of being a modern, media-savvy wife, and been willing to do a little more by way of appearing at her husband's side as charming upmarket arm candy.But she has not. No party hack was going to get her hands on Betsy's wardrobe.Mrs Duncan Smith, by all accounts, looked lovely at the Tory conference gala dinner in the sort of classic pink suit that the Queen's favourite couturier was famous for creating. She arranged a private consultation with the vendeuse at Hardy Amies and, with the help of a relative, stuck a deal whereby she could borrow their suits and eveningwear for public engagements.

Talking about her work with Ffion Hague, she said: "Wardrobe is an issue for women because it is a lot easier for men just to carry a few suits. People take pictures of William Hague as leader of the party but pictures of Ffion as Ffion."But even on this matter, Mrs Duncan Smith, was a different kind of leader's wife. This might not sound like such a big deal, but it's still a break with tradition. Until Betsy came along, no Tory spouse had deviated from the example set by Clementine Churchill, who mounted the platform by her husband's side, a model of loyalty.Mrs Duncan Smith did show up later, although she did not have a speaking role at the conference.

At that time, presumably, Tory party operators still had high hopes for Betsy, and were employing a strategy whereby they broke her in to service gently. She was assigned a personal adviser, Shana Hole, who had previously been in charge of projecting the image of Ffion Hague, and had also worked as a PR for Margaret Thatcher.Certainly, thoughts were already being formulated about how Mrs Duncan Smith's natural assets could be exploited Ms Hole once explained that her duties ran to such matters. Although her husband had been MP for Chingford since 1992, with Betsy playing her fateful part as his diary secretary from the beginning, she had never, for example, attended a party conference until her husband became leader in 2001.Even then, she did not manage to get down to Blackpool in time for Mr Duncan Smith's first speech on the conference platform as leader. She is, at first sight, just what the Tory spin doctor ordered.Except that, when you come to think of it, who has ever managed very much more than "first sight" of Betsy Duncan Smith? Not the party faithful. She's from an aristocratic background, loves the country life, and is not ambitious for herself, except as a wife, mother and helpmeet. Unhindered by intellectual credentials, she left school after her A-levels and worked at Harrods for a couple of years before training as a secretary.

She's blonde and beautiful, dresses with quiet panache and ubiquitous pearls, and believes in traditional Tory values like staying home with the children. On paper at least, Betsy Duncan Smith appears to be the perfect Conservative wife. The series, called Signs that say what you want them to say and not signs that say what someone else wants you to say, seemed closer to documentary photography than to art, as has a great deal of her work since (that was part of the reason she chose to show them first in a magazine rather than a gallery ). But they contained a subtlety, a quietly surreal intensity that undermined anything straightforward you could think to say about them.One of the most famous images from that series showed a young businessman in a suit holding a sign saying "I'M DESPERATE". The impact it had was like clutching a livewire, and it continues to shock today. But who knows what the man was really thinking? "I think he was very serious," says Wearing when I ask.