Dress: formal. Result: disaster

Why do the British dress up so badly? Famous for our sense of occasion we seem to have no sense of occasion wear. Send them a wedding invitation and normally well-dressed women will throw money at something in emerald green with shoulder pads. Stipulate "black tie" and sober suited men will truss themselves into noisy brocade cummerbunds. The nation's wedding photographs are a testament to bad taste and bad spending.

It could be genetic. There could be some deep, inborn reason why British women look less chic the more imortant the occasion and the more they lavish on the outfit. Ladies Day at Ascot, the wedding pages of Hello! and Debenham's changing room all provide ample opportunity for hilarious disbelief.

Men don't really have this problem. Largely because there is far less latitude in what they can wear to functions. You may not always approve of his ties, but you won't catch Tony Blair in a turqoise edge-to-edge jacket. A suit is a suit. It might not fit very well, but it's unlikely to look ridiculous in the wedding photos. This is the special prerogative of the bride's mother.

The strain of wedding arrangements seems to send an otherwise sensible woman into a tailspin of panic that leaves them gasping for breath in Selfridges designer department clutching a black and yellow geometric two-piece with orange piping. More depressing still, Brides magazine calculates that the whole shebang will have cost her an average of pounds 300. And she'll probably never wear it again.

Susie Faux, owner of the London shop Wardrobe, which prides itself on giving advice to the serious clothes hound, doesn't blame the shopper. "They're shopping in the wrong shops,'' she asserts, somewhat predictably. "A lot of people will tend to go to department stores. There is never any advice for formal occasions and people either underdress or overdress."

Maybe it's lack of example. The only women in public life sporting distinctive daywear are TV presenters and Members of Parliament - and their dress sense is virtually interchangeable. Sartorially, there is nothing to stop Joan Ruddock becoming a weathergirl and Suzanne Charlton taking over as shadow spokesman on environmental protection. The paintbox palette favoured by women in the public eye features high on Susie Faux's hit list: "Bright colours should be saved for somewhere where it's hot. They tend to show that a woman's unconfident. They're saying 'I'm not sure that you'll look at me unless I wear a bright colour'."

Clearly, few MPs have availed themselves of Ms Faux's advice. The gaily coloured, boxy collarless jacket (a tailoring dodge presumably dreamed up by someone who couldn't cut their way out of a paper bag) was pioneered by Mrs Thatcher after her makeover by Aquascutum in 1987. Ever since, the only female MP who looks as if she has got up, opened the cupboard, chosen some clothes and slipped them on is Virginia Bottomley. Virtually everyone else looks as if their wardrobe for the day was biked over from Alexon.

The Fuchsia Jacket Syndrome, exemplified by Harriet Harman reaches its glorious apotheosis in Teresa Gorman. Mrs Gorman, whose daywear can be summarised as Escada-a-go-go, clearly approaches every day in the optimistic belief that she will receive a last-minute invitation to a bar-mitzvah in Barnet. This may also explain why Margaret Beckett always looks as if she's just had a run in with a bag of Dolly Mixtures.

But at least she is in no danger of bumping into someone dressed the same. This proverbial sartorial embarrassment occurred repeatedly at this summer's weddings as fashion victim after fashion victim fell prey to the candied charms of the little pink suit. Some of the more fashionable nuptials looked like a Barbie doll convention. This collective unintelligence manifests itself periodically in social fashions and the herd instinct is particularly strong this year. Twenty years ago it was the frilly white blouse and black velvet jacket that upholstered the drinks parties of the middle classes. Today it's that sleeveless security blanket The Little Black Dress. Every season, designers announce the death of black and the birth of, say, tangerine and every season the buying public listens politely then tells them where they can stick their tangerine. Black is slimming and it doesn't show the dirt (crucial in a country that spends an average of pounds 19 per family per year on dry cleaning; America spends four times as much).

Susie Faux is a big fan. "The little black dress is the best thing that ever happened to women." Yes, but isn't it just a teensy bit boring? "It's never mattered for men's tuxedos. If only women could get to that position."

The little black dress has its origins in Parisian thrift. In theory its tasteful anonymity will blind your acquaintance to the fact that you wear the same ebony sack to every festive gathering. The soignee look its wearers have in mind would be all well and good if they were only willing to spend a few bob on their hair. Sadly, the typical Englishwoman's idea of a hairdo is to shampoo it.

Such habitual parsimony characterises the Englishwoman's wardrobe. Susie Faux is merciless in her condemnation of cheap clothes: "You can always tell a cheaper jacket. People who think you can just change the buttons don't know anything about clothes.'' Ms Faux doesn't reckon you can buy a decent evening dress for a penny less than pounds 500. Sorry I asked.

Menswear can be cheaper. Alan Bennett, an old school Savile Row tailor, reckons that pounds 350 would be the absolute bottom line for an off-the-peg dinner suit. He would, of course, rather you let him make it. This would set you back around pounds 1250 but, unlike most little black dresses, the result would last between 10 and 20 years. Black tie is enjoying something of a renaissance but white tie and tails is in serious decline. Expensive, seldom required and hemmed around by rules and regulations, the unpopularity of the old soup-and-fish is hardly surprising. Hardy Amies' unwitting comedy classic The Englishman's Suit is very strict on the matter: "It is not elegant to wear a wristwatch with tails. Sensitive men who lack a "dress" watch keep their wrist-watches in a waistcoat pocket". No wonder white tie parties have become virtually obsolete.

Black tie supposedly allows more "scope for individuality" but this is usually just a euphemism for the hideous waistcoats and bow ties that accompany it. Hardy Amies will have none of this: "You simply cannot wear a scarlet satin tie; it is overwhelmingly 'naff'. Nor may you wear any coloured or any patterned tie." Black tie abuse reaches its nadir at awards ceremonies. Hugh Grant manages to behave himself but British style gurus are outraged as star after star twinkles by in Nehru jackets, black shirts, polo necks ... Let's hope Hardy Amies isn't watching.

"The young can have their fling, but the fling should not go so far as to allow a white tie with a dinner coat," he frets. Tell that to Chris Eubank.

Avoid

Fuschia pink

Any print with flowers bigger than your head

German clothes (Escada or Laurel)

Be wary of

Sleeveless dresses - the upper arms is often rather a grey area at this time of year

Anything with a slit up the back

Remember

If it takes that much hairspray, you haven't had it cut properly

Try to imagine how you will feel about the photos in 10 years' time

Men, ask yourself: Do I look like a professional snooker player? If so, ditch the waistcoat

Women, ask yourself: 'Would Teresa Gorman/ Paula Yates wear this? If the answer is yes, stay at home

They've got it

When it comes to black tie, don't muck around with novelty ties, patterned waistcoats or Nehru jackets. Follow Hugh Grant's lead and play it straight

From the clothes she wears you wouldn't mistake the Princess of Wales for an MP or a weather girl, whose styles are entirely interchangeable. Note the absence of boxy jackets, gilt buttons and orange piping

They haven't

Not only does he wear jodhpurs and lace-up boots, but Chris Eubank is sporting a patterned tie, anathema to the school of classic British dressing subscribed to by Hardy Amies

Julie Goodyear suffers from the Fuschia Jacket Syndrome, which says 'I'm not sure you'll look at me unless I wear a bright colour.' The dangly earrings may be her trademark but they are also a mistake