Any mother about to attend school sports day for the first time needs to ask herself one question: 'Can I win?'

If your limbs are lean and limber, your sprint speed awesome and your hand rock-steady to keep the egg on the spoon, you may feel free to wear whatever you like.

As the suede-headed Sinead O'Connor demonstrated last week at her son Jake's sports day, it is fine to wear a scruffy T-shirt, track pants and running shoes as long as you are going to be first over the line.

But if you are not, grunge should be replaced by glamour. A first sports day is also your first opportunity to embarrass your child. Wear something dull and come last and the apple of your eye will be mortified.

It is all very well to dress to blend in with the crowd, but so much more delightful to turn up decked out as a child's idea of gorgeousness. Then you can bask in the knowledge that all your little angel's tiny friends will adore you, however badly you do in the sack race.

There are tricks to dressing to be adored by an infant school. Wearing pink, even if you normally wouldn't, is a good idea. But wearing Deauville-style floaty palazzo pants is a bad idea, as one mum found out to her chagrin just last week.

Decked up to the nines (she thought) in a brand-new purchase from Ralph Lauren, her child was appalled. 'Mummy] Stand behind that chair or people will see you in your pyjamas]' hollered her horrified daughter.

Armani is also to be avoided, both the super-pricey real McCoy and the many excellent imitations (including a cardigan-soft, muted striped blazer from Marks & Spencer). School-run mums tell me that sophisticated beige is already emerging as the adult school uniform for this summer's sports days. This is not good news.

For your taupe two-piece registers as a non-colour to a tiny tot. What child ever looked up lovingly at a parent dressed in something shapeless the colour of boring biscuits without any chocolate on and said 'Mummy, you look beautiful'? The only brown acceptable to a child is the colour of toffee, which, whipped up into a jacket and sailor shorts with clompy, Minnie Mouse-style matching shoes (and here labelled Gucci) looks scrumptious.

Better still, stick to the colour spectrum of a Mr Kipling cake selection. Then your child will think you are the loveliest mummy on earth. It is not often that I trumpet the appeal of Chanel, purveyor of clothes for trophy women with tiny handbags. But suddenly I get it. The real reason for Chanel's phenomenal success is that small boys love all the glittery bits and bubble-gum colours. Big boys are but small boys grown up, after all.

Big boys and girls, particularly those who work on tabloid newspapers, seem to think that the British designer Vivienne Westwood is a depraved lunatic. Such people would be horrified at the thought of her designs coming anywhere close to young innocents. But children love them. Not the fake chinchilla G-strings, of course, but the candyfloss confections. For Westwood shares with children the special secret knowledge that dream mummies look loveliest when dressed as sugar-plum fairies.

A (slightly) easier option is to wear a huge hat and a polka dot dress, which have a jaunty, cartoon appeal to children. But choose one which will stay in place while you Hula-Hoop.

At this point I can almost see the steam coming out of your ears. 'What,' I hear you scream, 'is the Independent doing reinforcing sexual stereotypes] We are assured, accomplished women. How dare you suggest we dress as fantasy figures?'

I dare to do so, because one fact holds true. Most little girls, no matter how many Tonka toy digger trucks you thrust into their hands, go through a stage, however brief, when they want to look like fairy princesses (and many little boys go through this stage, too). Next year, they'll be tomboys and they will hate that hat, that skirt, that blouse.

But by next year they won't want to do the three-legged race with you any more. By the year after that they will insist that they are far too grown up for the sack race. And then you'll remember that little face beaming with pride on the day mummy looked so pretty.

(Photographs omitted)