Who provides the royal wedding canapé? Royal purveyors, of course.

As if figuring out the guest list and sorting out the seating in Westminster Abbey was not complicated enough, the royals now also have a whole day and night worth of parties to throw.

And, with 600 guests arriving at Buckingham Palace Friday for Prince William and Kate Middleton's wedding reception, 300 expected for a gala buffet dinner in the evening, and an '80s disco planned to go all night, the logistics involved are immense.

But, while a mere mortal family might plan for such a big day by, say, shopping around and getting price quotes, trying out some DJs and caterers, or hiring a wedding planner to oversee the show, these are, to reiterate, the royals – and they do it all differently. They don’t, for example, shop around.

Sure, the royals can decide if they want cheddar or stilton to go with their crackers – but they buy their cheeses, as always, from Paxton and Whitfield, royal cheese purveyors since appointment by Queen Victoria in 1850.

And if it rains, as expected, they can decide if to open up the buffalo horn handle umbrella, or the plain old cherry handle one, but have no doubt about it, it will be from Swaine Adeney Brigg, royal purveyor of umbrellas since appointment by Queen Victoria in 1893.

“A royal would not walk into the supermarket and just buy cheese,” explains Gemma Ainge, a cheese monger at the family-owned Paxton and Whitfield, who refused to reveal any “indiscreet” information about the wedding choice of cheeses. “That is just not how it is done.”

Having a system of royal warrants of appointment means that whether what is needed by the royals is a new suit, hat, car, piece of stationery, bowl of cereal, banana, bug spray, an umbrella, or food for a wedding party – they turn to a small pool of official purveyors they themselves have selected, and have what they need sent over to their palaces.

In Britain today, some 850 individuals and companies hold the highly coveted warrants to supply goods or services to the royal family. The warrants, which must be applied for, can also be lost – if the quality of the service is not up to standard, or if the royal who granted the warrant dies and another living royal does not extend the grant – at which time the company must alter their packaging and stationery and remove the Royal Arms from their vehicles and buildings.

Today, warrants can be granted by three members of the royal family here – The Queen, the Duke of Edinburgh, and Prince Charles. And when Prince William becomes the first in line to the throne, and builds his own household, he too will be allowed to grant warrants.

“The warrants are a nod of approval, a sign of quality and an honor,” explains master tailor Kenneth Austin, who runs Benson & Clegg, the royal button and badge maker, as he proudly shows his handmade gold plated buttons.

“It has worked this way for centuries,” he says, and, despite the modern look and feel of William and his generation of royals, “… it is expected to continue working like this way for a long time to come... . It is a tradition, and while the younger ones might like to shop on the high street or allow themselves more choice – they will be guided by the Palace to find a balance respectful of their stature.”

Over at Charbonnel et Walker, royal purveyors of fine chocolate since being granted the appointment by King Edward the VII in 1875, the small staff is busy tying satin ribbons around special heart-shaped packages of handmade Champagne truffles.

“HRH Prince William and Miss Catherine Middleton, April 29, 2011,” reads the gold embossing on the lid. "It is a special time," says Jonas Cemm from behind the counter. "Let the celebrations begin!"