Royal wedding guests must be familiar with the correct form in case they should encounter a monarch or other royal personage.
Proper form: etiquette for weddings, royal or otherwise
Hat: check. Blow-dry booked: check. Labels removed from soles of new shoes: check. For those attending Prince William and Kate Middleton's wedding [lets out small squeak of excitement] tomorrow, the past few months must have been spent in a state of fevered list-making. It's not every day that you get invited to the wedding of the century, and everything has to be just right.
In fact, from the moment that leaden weight of an invitation plopped through their letterboxes back in February, the 1,900 guests who will attend Friday's service at Westminster Abbey in London will have been mentally running through exactly what needs to be done before the big day.
First, there's the outfit - preferably something simple and elegant (unless, of course, you're Zara Phillips). Then a suitable wedding present must be chosen - something for the cottage in Wales where the couple will live, perhaps. Anything with horses or dogs on it is a safe bet.
And finally, plenty of subtle mentions must be dropped into conversation so that everybody you meet is aware that you are unable to make any other engagement on Friday April 29 because yes, you say, faux bashfully, eyes cast meekly to the floor, you are attending the wedding of the future king and queen that day.
Guests may think their lists complete, but until they have also had a thorough read of www.debretts.co.uk, they will be horribly mistaken. For there, at the online home of all that is good and "proper" about British society (Debrett's describes itself as "the modern authority on all matters of etiquette, social occasions, people of distinction and fine style"), they will learn the dos and don'ts of conduct at the wedding.
Of course, the vast majority of the people attending will have a pretty good idea of what is expected of them. But with around 1,000 of them being friends of William and Kate, there are bound to be a few who are, shall we say, socially untutored.
With the entire British royal family putting in an appearance, as well as those of many other countries - among them Sheikh Mohammed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the Armed Forces - a regal encounter is not outside the realms of possibility.
"In conversation, address the queen as 'Your Majesty', and subsequently 'Ma'am' (to rhyme with Pam)," instructs Debrett's, should you find yourself in the powder room with the British monarch. That's after you have curtsied upon introduction. "The curtsy should be a discreet but dignified bob," it says. The bow expected of men, it adds, "is an inclination of the head, not from the waist". Not, of course, that you'll be in the powder room if you are a man.
Royal encounters aside, the traditional British wedding is a minefield of antiquated social mores, with a potential faux pas at every turn. Some may stumble at the first hurdle: replying to the invitation. This should, according to Debrett's, be expressed in the third person and be unsigned (one's name appears earlier in the text - as though written by one's social secretary, you understand).
Then there is the male dress code. It was reported recently that David Cameron, the British prime minister, would be wearing a morning suit to the royal wedding. This, according to Debrett's, is good form. In fact, there is an entire section of the website dedicated to getting this look exactly right - from which shade of tie should be worn ("softer tones look best") to the type of braces ("they should be made of felt and fitted with buttons").
Women have to cope with fewer instructions when it comes to their outfits, other than the obvious: don't, whatever you do, wear white. Hats are preferable to fascinators, and ought not to be removed until the mother of the bride (Carole Middleton, whose hat is the subject of almost as much speculation as Kate's choice of dress) removes hers. Likewise, men's morning coats must stay put until the groom takes his off.
Prince Harry, who is to be his brother's best man, is no doubt under strict instructions to keep his speech clean. There is nothing quite like the squirming embarrassment of a crowd digesting a barrage of inappropriate jokes about the groom and his stag weekend. On this, Debrett's is unequivocal: "The best man's speech should be witty and amusing rather than shocking; it must appeal to all generations. Jokes should be funny and light-hearted, never rude or smutty."
With 650 people attending the lunchtime reception to be given by the queen at Buckingham Palace, which is when the speeches will be made, the "something for everyone" approach could mean it running into hours (Debrett's says that the total speech time, including that of the groom and the father of the bride or equivalent, should last no longer than 45 minutes). Harry therefore has little choice but to keep his short and sweet.
The UK is not the only country where wedding etiquette is deeply entrenched. Here in the UAE, certain codes of conduct are also expected, says Heba Al Fazari, an executive image, etiquette and communication coach from Abu Dhabi, who often provides advice to expatriates attending Emirati weddings.
"As an expat guest coming to a local wedding you should know that absolutely no gifts should be brought with you to the wedding itself," she says. "If you know the bride very well it would be very nice to send something to the bride's house either before or after the wedding."
It is important, she says, on entering the ballroom, to introduce yourself to both the bride's and groom's families, who will be lined up, ready to greet guests. Although weddings are often large, with the guest lists running into many hundreds or even thousands, under no circumstances should an uninvited guest be brought along. And the seating plan, should there be one, must be strictly adhered to.
There are also several points to note with regard to the bride. "When the groom comes in at around midnight," she says, "with the bride's cousin and brother, it is expected that all the women in the ballroom, including the expats, cover up. It's not so much a modesty thing as that it's nice for the parents to put all the focus on the bride."
Cameras, she adds, are an absolute no-no. "This has religious connotations because the ladies who are normally covered or wear the hijab, they take it off at the wedding because they are all women, but then if somebody takes a photo of them and it is seen by somebody else, they do not want this."
Finally, with the dinner usually a buffet, guests should refrain from eating until everybody at the table has returned from the self-service area and is seated again.
Wherever the wedding may be, there is always, it seems, a rule book of sorts. Jerramy Fine is an author who runs Princess Prep, a residential course in London where American girls aged eight to 11 are immersed in the "princess experience" (they have daily etiquette lessons and learn about princesses of the past). Her recent book, Someday My Prince Will Come details her escape from America and her attempt to become an English princess, and she has her own fairy-tale take on the subject: "Have confidence and believe in yourself," she says. "If you carry yourself with the grace and dignity of a princess, you have every right to move in regal circles."
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