Rowan Pelling: Everyone needs an unsuitable friend

At primary school, I was briefly barred from playing with another little girl. My misdemeanour was that I had constructed a human bridle from old bits of horse tack found in a farm stable and had made my friend wear this contraption while I "trained" her with a riding crop. My mother received a note from the girl's mother demanding that "Rowan must stop whipping Julia".

I can still remember the ignominy of being thought "a bad influence", and I imagine my mum was not so chuffed that her 10-year-old was being viewed as a mini Marquis de Sade. Now the knives are out for Guy Pelly, a "wealthy landowner's son" (for which read, "upper-class twerp"), dubbed by the tabloids "unofficial court jester" to Prince William and his set.

Pelly was accused of being the person who introduced Prince Harry to dope three years ago, and has now been shopped to the press for smoking cannabis on a night out with Prince William last weekend.

According to a police source in the Daily Mail: "There is enormous concern about Pelly and the 'fast-and-loose set' that he keeps company with ... Pelly is a friend they would be better off without." In what way? So the princes can hang out with a gang of squeaky-clean, blazer-wearing freaks? The kind of pompous prats who might say of Pelly, as a "member of William's circle" did, "It's pathetic, but William and Harry think he is hilarious"?

Yup, exclude Pelly for the heinous crime of telling crap jokes and rolling joints, so turning those Windsor boys into men of the people.

Previous generations of royal males knew the value of unsuitable friends. These obliging scallywags have always had a vital role to play in drawing flak away from mates whose public profile means that they must always appear spotless. The Guy Pellys of this world were born to absorb blame on behalf of others. The drugs, booze, gambling debts, blondes, strippers, call-girls and any ill-thrown punches are the jester's burden. This is what is known as the royal prerogative.

Shakespeare knew that every Hal must have his Falstaff. Prince Philip was reputed to have used racy actor friends, such as Douglas Fairbanks Jr and David Niven, as covers for his interest in certain glamorous females in his younger days. Edward VII had a positive embarrassment of dodgy hangers-on when he was Prince of Wales. And what about the late Duke of Windsor? His best mate was an aristo called "Fruity" Metcalfe. Need I say more?

I don't think I would have any mates left if I threw out all the unsuitable ones. One of life's greatest comforts is knowing that, however badly I behave, there's always a friend at hand who can, and usually will, do something far worse. Though I knock back the booze, I've begun to think of myself as a teetotaller because I have several close friends who hit the bottle with such panache even winos look startled.

Of late, I have realised that it's not the drinkers, the druggies and the nymphomaniacs who have the worst influence on me. That accolade goes to my new friend, Christobel, a supposedly respectable author and mother of five. This smiling assassin, with her seemingly innocent penchant for 1940s jive, wantonly introduced me to something far more harrowing, addictive and destructive than heroin.

That's right, she showed me how to bid for vintage clothes on eBay. As I stood transfixed while she expertly raised the last-minute bid on a black crêpe de Chine cocktail frock, she flashed her dark eyes at me, laughed dangerously and whispered, "What else is Child Benefit for?" Days later I was spending my son's milk money on Biba originals and Charles Jourdan disco sandals.

Unsuitability, like beauty, is in the eye of the beholder. There might be those who feel that Guy Pelly should think twice before hanging out with a young man who dresses as a Nazi at fancy-dress parties and is descended from Hanoverian in-breds.

When I was at secondary school, I had a friend who was among the most precocious in the year. She offloaded her virginity at 15, smoked, shoplifted, bullied and drank like a fish. It was surprising to learn, years later, that her strict parents regarded me as the bad influence. My friend had blamed me for missed trains home from London and lifts needed in the small hours. (The true reason was she was necking with some drooling youth.) But I am grateful to my friend for leading me astray at an age when I sorely needed louche inspiration.

I am sure that Princes William and Harry are equally in debt to Guy Pelly for introducing a little pot, prattishness and normality into their straight-laced lives. If you take a close look at the boorish stuffed-shirts who constitute Prince Charles's circle, you can understand why HRH is rarely accused of being in touch with reality.

The problem is, Guy Pelly is not unsuitable enough. William should be made to hang out with some happy-slapping hoodies on a south London estate if he's really going to drag the monarchy into the 21st century.