A night at the Natural History Museum – just don’t try doing what comes naturally at this sleepover for grown-ups

There are three rules when sleeping over at the Natural History Museum. First, no stag parties. Second, go easy on the booze. Third, no sex.

“We understand there’s nothing sexier than a room full of dead animals,” our compere says at the welcome dinner for the museum’s “adults-only” night. “But please don’t go there. Sex and skeletons don’t mix. You will be thrown out.”

Yet from the moment my wife and I set foot in the museum on Saturday night, one topic seems to dominate conversation. Over dinner we sit with Erica McAlister, the museum’s resident entomologist who explains Britons’ growing predilection for making out in museums. Proprietors have, she says, interrupted intimate relations between “determined” visitors, and occasionally staff, so frequently that the simple instruction has to be repeated: “No sex please – we’re scientists.”

Unlike the children’s version, “Dino Snores for Grown Ups” is a strictly adults-only affair. A dimly-illuminated lecture on the sex-lives of insects documents, among other topics, the gradual extinction of body lice due to the global shunning of bodily hair.

When the lights in our makeshift bedroom – the museum’s resplendent Victorian entrance hall – are finally switched off at 3am, burly security men patrol the premises, shining suspicious torches on stirring sleeping bags.

Earlier, at midnight, my artistic wife opts for dinosaur drawing classes while I head to the dining room for a five-course degustation of edible insects. First up, a bamboo worm (it tastes like the soft part of a pork scratching, very salty); then a weaver ant (think popcorn with an elongated crackling in the back of the mouth); next, a toasted silkworm (high in protein, low in fat); a giant mole cricket (disintegrates between your teeth with a bitter aftertaste); and, finally, a weevil beetle (twist and chew – tastes like crispy bacon).

In truth I’m feeling slightly nauseous by 1.30am, as a harpist plays beneath the diplodocus where we’re camped. It’s time for a lie down. Mrs Dutta returns from the Wildlife Photographer of the Year Exhibition and we share an intimate moment together. Not that sort – the harpist is playing the melody that accompanied our wedding last summer.

Few could not be moved, hearing Pachelbel’s Canon bouncing from the cavernous, cathedral-like vault of the 132-year-old building, an experience that, alone, almost validates the £175-a-head tickets (although crisps and bottled water at £1.50 a pop feels akin to overnight robbery).

Throughout the night, people bond. We meet Rebecca Collins, a 28-year-old project manager from Brixton, who makes no bones about one of her main ambitions for the evening. “I’m hoping to find my future husband. He needs to be someone who is ‘geek chic’; attractive but unaware of it. Must like dinosaurs. Glasses and beard optional.”

Meanwhile, Ash and Sabz Sheikh, both in their 40s and dressed in camouflage costume, are celebrating their tenth wedding anniversary. Neither has any plans to sleep. Ghost stories are told throughout the night, and between 4am and 6am a selection of films is shown, including Jurassic Park and Arachnophobia.

We’re woken at 7.55am and make our way to breakfast. It is only then that I realise sleeping on the marble floor of a draughty museum is hardly the perfect night’s rest. And yet I feel revived. Our host thanks us for spending a night in “our anachronistic and weird hotel”.

I can only concur. Looking for a New Year’s resolution? Leave the kids at home and book your next romantic getaway underneath the diplodocus. Six such events are scheduled for 2014. Just don’t forget the golden rule…