Look Kate Middleton, all the best families have a black sheep

Forgive me for writing out of the blue but I grabbed the Basildon Bond as soon as I heard that the Middleton skeleton seems finally to have tumbled out of your tidy family closet.

Now, I'm sure you don't want everyone reminded but according to those nasty tabloid reporters who have caught him in a classic sting in his pad on "party island" Ibiza, your mother's little bro is a bit of a wild one.

Not to put too fine a point on it: a pimp and drug dealer who lives in a house called Maison de Bang Bang. You and your boyfriend Prince William - whose mother, Diana, worked for charities that supported drug addicts - have recently stayed at this bordello as his guests.

Your maternal uncle and host, meanwhile, has several tattoos; one says "Nouveau Riche" - an unwelcome reminder that your mother, Carole, a former air hostess, or should I say flight attendant, has been subjected to the most unpleasant crack of "Doors to Manual" when she graces social events.

And worst of all, as the whole world now knows, your maternal uncle's Christian name is Gary. Obviously, there's no coming back from that one.

Anyway, your Gary claims he is "bloodline" to the Royals and jokes he will take the title of the "Duke of Slough" when you and Wills tie the knot, he says maybe next year.

Look. I know, all this sounds like a dealbreaker to me too - one would have thought that the Royal Protection people and security services would have checked - so I'm not remotely surprised you're all having kittens at Mum's Party Pieces offices in Reading.

All you poor Middletons must be ever so worried that the Royals are going to call the whole thing off.

So this is why I've put pen to paper, because what I want to say is, don't worry! Listen. By long tradition, all the greatest houses in the land have a black sheep.

Riot, debt and dissipation are all de rigueur among the aristocracy. Just look at Jamie Blandford, heir apparent to the Duke of Marlborough. He's always burned the candle at both ends. Look at the Herveys or the Bristols or whatever you call them.

The sixth marquess was jailed, and daughter Lady Isabella was the face of Playboy UK, so in fact, there's hardly a white sheep among them. It's very smart, très snob, in fact, to have a black sheep in your midst - even if he is called Gary (and I must say, from my viewing of the videos of him cutting coke etc in his charnel house, Gaz looks like the life and soul of the party!).

One of the country's most distiguished chroniclers of the upper  classes, Christopher Simon Sykes, has written a whole book celebrating the black sheep.

And no wedding is ever complete without the naughty uncle propositioning the bridesmaids or slipping Rohypnol into the champers. Frankly, families that attempt to hide them away (in the old days, the black sheep was always sent off to the colonies as a remittance man) are always rumbled in the end, whether by the red tops or not.

So never fear - this is an essential rite of passage. With the emergence of Gary Goldsmith, you Middletons have entered a most exclusive club.

As I think you'll find as soon as you join the Firm, my dear Kate, all the very best families have a black sheep. Sometimes, a whole flock of them.

Chin up,

Rachel

Rachel Johnson is editor-designate of The Lady magazine.