Liz Hoggard: We must all admit our dodgy uncles

For heaven's sake, everyone's got a dodgy uncle. No doubt there will be hand-wringing over yesterday's News of the World allegations that Kate Middleton's uncle supplies cocaine and hookers. Questions will be asked about whether she's a fit consort for a future king. The whole ghastly "doors to manual" slurs about the Middleton family will be trotted out. But isn't there something rather delicious about the whole affair?

I don't know whether to hug or punch Kate's uncle: a balding, tattooed playboy called Gary, 49, who lives in a kitsch-filled £5m Ibiza villa called La Maison de Bang Bang ("French for House of Nookie," as the paper helpfully explained). Caught up in a NoW sting, he is said to have bragged that he greeted Kate's boyfriend Prince William for the first time with the four-letter salute: "Oi, you f***er!" And the loose-lipped Gary claimed that Wills has a penchant for chatting about breasts over the Middleton family dinner table.

My heart goes out to Kate, a nice young woman trying to lead a blameless life until some chinless wonder decides to mary her. But actually I think Gary has done us all a service. Every family has a skeleton in the cupboard.

My own dodgy uncle married and bankrupted a series of women, spent the family inheritance on model railways and went to prison for tax evasion (we never quite got the full story; my horrified grandfather whispered the news as he was moving a grand piano). It was painful for my cousins who handled the affair with dignity. But, as a swotty, unpopular teenager, I can't tell you how my stock rose having a convict in the family.

And naughty Uncle Gary just adds to the gaiety of a nation. In fact it's been a bumper weekend for royal watchers. News broke that the lovely Princess Eugenie is going to study at Newcastle, while Prince Charles is threatening to sell the beleaguered family business (Duchy Originals) to that vulgar upstart Waitrose.

I howled at the thought of the Prince behind the cheese counter. "The more middle-class they become, the more you love them," observed a friend tartly. But he's right. Soon they'll be joining my own family hinterland of curtain tie-backs and Dubonnet and boiled sweets for long car journeys. I already love her Maj for keeping the muesli in plastic boxes and giving Princess Anne an ironing board for her birthday.

As for La Maison de Bang Bang – there's rich material for a Mike Leigh film here. I'd suggest Jim Broadbent for Gary and Tamsin Greig as his girlfriend Antonia, 26, a former estate agent and lapdancer. I especially love Gary's apparent boast that he wants to drag the royal family into the modern age of the clubber (pumping his arms in the air, he yelled: "I'm going to change the royal wave to that – having it large!").

Critics claim the Middletons are bringing our first family into disrepute (remember Kate's little brother, James, dressed in a French maid's costume?). But actually they just make them more lovable. I have no time for the trustafarians who charter private planes and start galleries of Russian art but decline a proper day job. Give me an aspirational, middle-class family any day.

I hope Will and Kate don't lose their nerve about the engagement. Certainly Gary ("Call me 'Duke of Slough'") won't be giving away the bride. But the bluebloods needs a dose of vulgarity in the gene pool. Let us not forget that William's own family has its own dysfunctional, hilarious aspects.

For me, I'm suspicious of anyone who doesn't have a dodgy relative – it teaches you empathy. And the great British public, currently knackered, in debt, guilt-stricken about the in-laws, could do with some of that.