Dom Joly: You can't beat a beach holiday for jealousy and vice

I'm in St Lucia on a half-term getaway with the family. We don't normally do this kind of break, but we were suffering from a peculiar new breed of pressure – from the classroom. For the past year or so, we've had subtle hints from Parker about the quality of her half-terms, which normally involve a trip to the local swimming pool and an evening at Pizza Express in Cirencester. This, apparently, will no longer do.

"Maximillian has been to Barbados. What's Barbados, Mummy?" she would ask, coyly, at the breakfast table.

"Bruno has been skiing in Gstaad. What's Gstaad, Daddy?" She'd flutter her little eyelashes in early signs of dastardly use of her womanly wiles. I can't believe that we actually succumbed to the pressure but then again, it's hardly a trip to Toys'R'Us in Swindon – it does have its fringe benefits for us as well.

I'd forgotten how similar these types of resort hotels are to an Agatha Christie murder novel. You slowly start to recognise people around the pool and a cast of characters quickly emerges. There's the ultra-fit couple that never wear a shirt and stroke their perfect pecs all day in an auto-erotic manner as they devour health and fitness magazines and pints of fresh fruit juice.

Then there's the honeymoon couple – all loved up and constantly pawing each other over breakfast, lunch and supper. They're the only ones that really relish the idea of a Caribbean Valentine's night. They even booked the treehouse replete with violinist. Stacey and I hid in our room and watched The Driller Killer, a video nasty in which loved-up young childless couples get bumped off in increasingly horrible ways (mostly with an electric drill, hence the name).

There's also the middle-aged American couple who are irritated by absolutely everything – the heat, the cold, the noise from kids, the fact that the place is dead quiet and that there's nothing to do, the food, Bush leaving office soon.... You really wonder why these types ever leave Fatbutt, Ohio, at all.

Having done my best Hercule Poirot investigation, I'm hoping that the boring man who is never with his wife but constantly "entertaining" other tables with his stories of how many times he's been here and what you should and shouldn't do, gets thrown to his death from the treehouse by the weird lone guest in long trousers who spends all day on his mobile.

I'm then going to fit up the American couple for the crime and steal their sunbed position as they tend to creep out early every morning and reserve one. What is the legal position on sunbed grabbing? Does putting a book or a bottle of sunscreen on one make it yours for the entire day under St Lucian law? I like taking the reservation items off sunbeds and hiding them. I then settle down and watch the huge fights that happen between unsuspecting new users and the original early bookers. We've already had one fist-fight thanks to me – it's top entertainment and will doubtless soon be a television project.

Contrary to popular belief, we English are just as bad as the Germans in these early-bird raids to secure the best pool positions. For a television show, I once covered half a Cannes beach with a huge towel about the size of a tennis court and decorated in the colours of the German flag. We watched as the beach filled up but not a single person encroached on my "towel". When it was chock-a, I arrived in lederhosen and sat contentedly, staring at my crammed-in neighbours. Maybe I should apply this process to house purchases. I could just arrive early in the morning at the Cotswold mansion of my choice, leave a Jilly Cooper book and a towel on the doorstep, return in the evening and hey presto, the place is mine.

One of the other disturbing behaviour patterns on this holiday is that parents, particularly Brits, are visibly terrified of letting their kids roam more than 10 feet from the swimming pool. There are constant panicked screams as a mother discovers that little Timmy is missing and a search party is formed only to find that he is sitting stroking a cat behind a rhododendron bush. Even Stacey has succumbed a little, and does this ritual of checking that all the doors are locked about three times before she can rest her weary head. I also have a ritual – it involves four large rum punches.