Only suckers go shopping on a Saturday. I'm never going near a clothes shop on a weekend again. And certainly not with my mother and sister. Imagine two lithe fairies skipping around pinching imaginary rolls of fat and tutting over non-existent cellulite. I stopped discussing weight with my mother the day she trilled: "I know darling. I get so depressed if I reach 8st 7." Grrr.

Then my sister is like an Exocet missile when she gets going. I was still pondering over a pair of fatigue trousers (is it un-PC to wear them?) when she, like a dervish who has already sniffed out three bargains and terrorised a shop assistant into reducing the price on a slip dress, whirls round holding a similar but somehow more flattering pair. "I was just going to try these on," I say.

"I'll join you," she replies.

So now I have to brave the horror of the communal changing room. At least I've been ill so I'm slightly thinner than usual. (Every time I get ill I'm very happy. The feeling dreadful bit isn't great but the day off work and the lost pounds more than make up for it).

I'm sure when everyone else thinks of being Prime Minister they want to reform the welfare state or stop children smoking. I'd ban communal changing rooms.

Whenever you go in one there's always some long-limbed beauty prancing around in impossibly small bits of chiffon saying "Gosh I look dreadful" to her fat ugly friend who says "No you look wonderful". FUF shrugs on one top very quickly and takes it off, saying she looks dreadful. The beauty does not disagree.

Everyone else performs extravagant gymnastics trying to get out of jeans and a tight T-shirt and into a little black dress without more than an inch of flesh showing. Everyone tries not to look in the mirror but is really.

A fight nearly breaks out when my sister stands on a bit of chiffon by mistake. I hide in one of the few curtained -off areas.

"What d'you think?" pirouettes my sister.

"Great," yells my mum from the entrance. There is a long pause.

"What about you Glenda?"

"Oh, erm... I'm not sure about these..." I mumble.

"Do you want a bigger size?" asks my mum.

"No," I hiss back.

"Darling, I can't hear you. DO YOU WANT A BIGGER SIZE?"

"YES" I yell back.

All the sylphs turn to look. Someone giggles. There is a tearing sound. My sister has trodden on the chiffon again. She manages to get a reduction.