The Las Dunas Beach Hotel and Spa, Marbella, has an extremely bottom-themed multi-form art exhibition on show in its foyer. I don't know if whoever programmed this exhibition was conscious of the prevailing arse motif, or if it just evolved due to personal taste, but I like it a lot. Vast oils of women showing off their bottoms complement exquisite sculptures of women showing off their bottoms. The message seems to be: "Our hotel is not corporate. We do not pander to clientele who may not like to be confronted by a sea of bottoms upon check-in. Yes, our singular vision may be a little freaky, but it is a singular vision nonetheless."

Then, after check-in, you can wander down to the fantastic pool and swim in the shadow of many handsome men wearing pith helmets. I think they may be security guards, although I'm not sure. There are no breaches of security during my week at Las Dunas, so they never spring into action. Instead they stand there, like human statues. I like it a lot. So does Dale Winton, on whose conversations I spend my idle late summer days attempting to eavesdrop. "Indomitable flirting," he says, in reference to his conversations with the pith-helmet men, "is my forte."

I think Dale Winton and the Ronsons are the only people sitting around the pool - besides the children, I presume - who have not succumbed to plastic surgery. In fact Marbella's biggest plastic surgery clinic, the Molding, is just down the road from Las Dunas. It is a marble palace, a vast paean to surgery. To enter, one walks up the giant double staircase, in full view of the traffic. But nobody seems to care. It is no guilty secret here. For an hour or two one afternoon, I scrutinise surgically-perfected breasts intensely. They wheeze for breath underneath tiny leopard skin bikinis. Along with the pith helmeted men who stand behind them flexing their substantial muscles, the whole thing looks like a David La Chapelle tableau come to life. Oh, I think, if these people could see a La Chapelle photograph they'd feel suitably chagrined. Then I see a poster heralding the arrival of a major David La Chapelle travelling exhibition. How odd to glory in one's own grotesque caricature.

And then to dinner - in the Las Dunas' Michelin star-awarded Lido restaurant. The scallops with red wine noodles are amazing. The star couldn't be more deserved. It is just a shame that we Ronsons seem to be the only family in the restaurant having a good time. Everyone else looks bored. Bored, bored, bored. Bored with their children, the sun, the food, their seemingly limitless riches. They are the Marbella idle rich. I always fancied being idle and rich. Now - watching them up close - I am happy to be comfortably off and busy. Their perpetually bored facial expressions drive me mad. They are like black holes, sucking in all our holiday joy.

A funny thing happens to me on day three. I begin to feel that if I remain in Marbella long enough I will, like a victim in Invasion of the Body Snatchers, mysteriously transmute into a member of the Idle Rich. This is, I realise, unlikely. One has to be rich to be idle and rich - and I'm only, as I say, comfortably off - but I find myself becoming overwhelmed by a wave of guilt.

"This is not where we belong," I yell over-dramatically at my wife. "We are not swans. We are workers."

"Yes, yes," sighs my wife. "Whatever."

We wander through the marina in nearby Puerto Banus, staring at the giant yachts. The visitors' guide describes Puerto Banus, enigmatically, as "Think of Bang and Olafson and that's Puerto Banus." Maybe they came up with this metaphor because there's a Bang and Olafson right next to the taxi stand. Puerto Banus has every designer store you can imagine, and they nestle busily together like stalls in a noisy Turkish bazaar. Then we stop. A limousine cruises past, followed by another limousine, followed by a dozen limousines, a police guard, and another dozen limousines.

"Who the hell..." begins my wife.

"It's got to be Elton John," I say.

In fact it is King Fahd of Saudi Arabia. He's winched out of an armour-plated Mercedes on some weird hydraulic pulley system and hoisted, via something that can only be described as a posh crane, onto his yacht, the Al Diriyah. Then he vanishes inside, not to be seen again.

"That yacht's got to be bigger than our house," I say.

"The yacht is about 20 times bigger than our house," says my wife, slightly annoyed that I am so far removed from this world that I can't come up with a better simile than that. I think my wife wishes that we were slightly more idle and rich.

King Fahd had a stroke in 1995, hence his inability to move on his own. A crowd forms. Porsches and Ferraris pull up and the drivers stare out at this rare event - a chance to glimpse King Fahd in person. They whistle in admiration. He is like the patron saint of Marbella, the richest, glitziest and most powerful man in town. He is also - although this isn't his fault - the most idle. As I scrutinise the crowds who scrutinise him, I wonder if they're jealous of this super-idleness. Perhaps, in Marbella, not moving at all is the greatest status symbol one can achieve.

I tend to compare all family holidays to the greatest family holiday in the world: the Forte Village in Sardinia. The Forte Village is - like Marbella - hugely expensive, but here's the difference: at the Forte Village people act like they've saved up all year for this treat, and nothing will stop them from having fun. In Marbella, people behave like they do this every day, day in day out, the lovely food, the giant yachts, the sun, and they're bored, bored, bored.

I don't blame them for not appreciating the beach, though. The coastline of Marbella is reminiscent of the sand ashtrays you find in hotel lobbies. There are more cigarette ends than shells, more cigarette ends than pretty stones that children like to collect. The sand is dirty mud brown. On the first day, when I was still looking on the bright side, I said to my wife, "Just because the sand is the colour of mud, it doesn't mean it IS mud. It's still sand."

My wife replied, "But is there really a difference between mud-coloured sand and mud?" She was right. There's no difference. As much as I liked the Las Dunas - and especially their food, which is among the best I have ever eaten - I don't think I will return to Marbella. The Idle Rich blew it for me. Freud once wrote that there are only two things that matter in life: love and work. In cutting themselves off from both, Marbella's idle rich seem to have chosen for themselves the worst of all fates. In the end, the overriding atmosphere of boredom that pervades the town made me bored too.

· The Leading Hotels of the World offer one night in a standard garden view room from £162 per room per night including tax and service. Reservations through The Leading Hotels of the World on 00800 2888 8882; www.lhw.com