Manolo Blahnik, the shoe designer who regularly causes grown women to drool over his erotic strappy high heels, has unexpectedly increased pulse rates with his new flat shoes. The simplicity. The purity. The absolute chic of them. When high heels were all the rage, the more straps, buckles, twiddly bits, and embroidery applied to each one, the better. The new flat shoes that appeared on practically every catwalk for autumn/winter, on the other hand, are bereft of any detail whatsoever, and this is where they become interesting. To make up for the loss of detail, totally impractical luxury fabrics such as cashmere, grey flannel, satin, and wool dog's-tooth have been used instead.

The shoes pictured here were designed by Blahnik for the Cerruti show. They cost pounds 240, are made from superior grey flannel and are as light as a feather - just imagine the state of them after a day walking around town. A spokesman for the designer asserts that they are in fact very hard-wearing, but we're not so sure. Expect to wear clodhoppers outside and slip the flannel slippers on once inside your bijou apartment, groovy drinks party or other Manolo-ish setting.

Grey flannel is definitely having a fashion moment. It is the colour and fabric for clothing, as well as the most popular fabric for this season's footwear. Gina, Sportmax, MaxMara, Bertie and Office have offered it in all guises, including high-heeled courts, but primarily in flat doll-like Mary Janes (that's the new strap-fronted shoes, of course), ballet pumps and mules that look like slippers. Unfortunately the Office version, a Prada-esque Mary Jane with a moulded rubber sole and Velcro strap, won't be available until October.

Flannel is certainly more hard-wearing than cashmere, and looks just as good. One bright spark did give that cashmere shoe thing a try. It was Narciso Rodriguez, who, for his own label, customised the Boston clog by Birkenstock with the luxury fibre and styled them with thick socks. The problem? The clogs have not been manufactured. Birkenstock has been deluged with enquiries. "It's great that Rodriguez has done it," says Fern Whamby, Birkenstock's UK agent, "but very misleading for the public." However it is wonderful news for Birkenstock, who are able to tell enquirers that it has the Boston in, you guessed it, grey flannel, for pounds 37.

There is some consolation for those in love with the idea of cashmere shoes. The mail-order company Toast, which specialises in luxury lounging gear, has produced extremely soft cashmere espadrilles in beige and black, from pounds 79. Alternatively take some advice from Mr Blahnik who suggests, "an incredible grey cashmere stocking worn with the most divine sort of mule is, I think, the chic-est thing". Yes, and also the most expensive, Mr Blahnik.

Toast, orderline 01558 668800; Manolo Blahnik 0171 352 3860; Birkenstock enquiries 0800 132 194.