Socially- and sartorially- speaking, Royal Ascot is THE event of the season, when common punters can place their bets in the hallowed presence of the British royal family.

All sounds positively delightful, doesn't it? A day at the races rubbing shoulders with hooray Henry and pals — but there are some serious rules to be followed, and it's not about how to act around the upper classes. Its about how to dress.

Ascot officials, reacting to photos published in the British press of last-year's less-than-chic racegoers, have come up with a dress code for those hoping to gain entry to the Royal Enclosure. (Entrance to the enclosure not only costs Dh590, but depends on sponsorship by someone who has already gained access to the Enclosure on four previous occassions.)

Hilarious

On the Ascot website, a hilarious slideshow aping Glamour magazine's do's and don'ts page features unfortunately-attired young fillies in — shocker — halternecks, flimsy shawls and spaghetti straps. In perhaps the most chilling edict, a photo shows a girl with a few feathers clipped to her hair with the thunderous caption: “insubstantial fascinators NOT ALLOWED".

At this juncture, one, therefore, must ask oneself: Will Dubai's World Cup — with its hotly contested chav stakes — come in for the same directives next year? An unspoken (by the organisers, anyway) rule at Ascot also requires the avoidance of any streaky fake bakes.

One reporter giddily remembered the day it rained at the Melbourne Cup, recalling how “rivers of brown" poured into the gutters. Rain isn't too much of a worry here, but a little less orange would be much appreciated.

So what's permitted at Ascot? Apart from the website's “do" suggestions — all of which can be picked up in the Matronly aisle at a department store near you — it's recommended that shoulder straps be at least an inch wide, hats must be worn, and trouser suits, while acceptable, should be “full-length and matching colours". Dammit! There goes my pink-and-green cutoff suit scheme.

Above the law

Mini-skirts too, are taboo, although Princess Eugenie, who attended the first day of the event with her sister and occasional fashion plate (not on this occasion) Beatrice, seemed above the law. Her skirt, while not exactly a miniskirt, was at least two inches above the knee, a dress altitude deemed unaccaptable by the steward guarding the entrance of the enclosure, who told The Times he wouldn't let lower-class versions in dressed like that.

In the grand tradition of those sisters, they both wore breathtakingly tight jackets, Eugenie's a deep blue befitting her royal status, Bea's a black topper on her Alexander McQueen (again?) ensemble. Eugenie wore a dress by Collette Dinnigan.

Bea and Eugenie were also in the company of Queen Elizabeth and high-ranking members of the royal family, all suitably turned out in soft pastels. But first past the post in the fashion stakes was undoubtedly Zara Phillips, the queen's granddaughter and a top equestrian herself. She teamed her creamy, rose-trimmed Philip Treacy hat with a pussy-bowed cream satin blouse and fullbodied-black Ralph Lauren skirt.

Gentlemen prefer toppers

Ascot, the annual outing for the top hat, is upon us again. To mark the occasion, Robert Colvile dons his tails and goes in search of one of the last bespoke hatters in Britain

For Londoners of a certain generation, a top hat was de rigueur. “Not merely did one hunt in it, as one still does: one fished, one skated, one played cricket in it," recalled a wistful Max Beerbohm. “One wore it through debates in the Houses of Parliament, taking it off (with a wrench) only when one rose to orate, and resuming it (with a sigh of relief) as soon as ever one had said one's say."

Beerbohm, writing in 1940, was convinced that the day of the top hat had passed. But more than 60 years later, we are still in its thrall: today, at Royal Ascot's Ladies' Day, a top hat will be as vital a part of the gentlemen's wardrobe as an extravagant piece of millinery is for the ladies.

Yet in one respect Beerbohm has been proved right: a proper topper is a thing of the past. The necessary supply of luxury silk was disrupted by the Communist revolution in China, and the last looms capable of spinning what was left were destroyed in the 1960s.

The remaining supply of old-fashioned black silk numbers are tailored and traded by only a few outlets — chief among them a cramped basement flat in Chelsea, home to Martin Ellis Jones, and to his business, Hetherington Hats.

No sooner have the greetings been made than he sets about me with what sound like — and resemble — medieval instruments of torture: the conformature and formillion.

In fact, these antique wooden contraptions are the haberdasher's chief tools. The first sits on my head and maps its shape on to a tiny piece of card at the centre (the “conform").

The second takes that card outline and translates it, via dozens of little wooden levers that radiate from the centre, into the appropriate shape for a fully personalised brim.

“You have a long, thin head," Ellis Jones informs me, “so anything other than that will make you look like an oaf." My hat size, seven and a quarter, is a fraction above average: disappointing to Ellis Jones, who favours the smaller skulls that betray properly aristocratic inbreeding.

I can, however, take pride in the company my “conform" will keep: the Aga Khan, rugby player Matt Dawson, Spice Girl Mel C. “We have all sorts of people in here," Ellis Jones confirms. “Brian May came in the other day at quarter past 12 and didn't leave until after two."

If you want to shine at Ascot, it's not simply a case of picking the most expensive model. “A top hat's a very flattering thing," says Ellis Jones. “Once it fits, it looks wonderful. But if it doesn't fit, it looks bloody awful." He demonstrates by offering me one that's slightly too broad and slightly too long. I reckon it quite suits me, but he tuts furiously: “You look terrible."

Such precision comes with a price: the hat I have been modelling would set me back approximately £3,500 (Dh25,000).

I should not, as others suggest, tilt the hat at a rakish 10-degree angle. “Absolutely flat on your head," I am told firmly.

For Ellis Jones, this seems to be as much a labour of love as a profession. He insists that I see his favourite topper: “I will burst into tears when I sell this, because it is the best hat anyone has ever encountered. I always quote a price that's too much for anyone to buy."