The house, a classic square-fronted affair with large windows that glint in the frosty winter sun, sits solidly amid manicured lawns surrounded by sweeping landscape. “It’s a set piece - an absolute gem of Georgian architecture,” my companion says. “Designed by Joseph Pickford - one of Derbyshire’s most prominent architects. He had a brilliant stone-carver called George Moneypenny - we can see his work over the door here.”

I nod and make appreciative noises. I don’t know much about architecture, but my guide does - a lot. So do his friends, an erudite group who, once we pull up at the elegant front door of this Derbyshire mansion, spill out of their cars excitedly, exclaiming over the beauty of the honey-coloured stone, the classicism of the high ceilings and square rooms, the fantastic views across the surrounding countryside from the roof. One pair enthuse about the piano nobile; others go into raptures over the gardener’s cottage, cunningly disguised to look like a classical Temple of the Winds.

Our host, an elderly man in tweeds, serves sherry and cheese shortbread, and engages in discussion about some of the ancient paintings hanging on his walls. The group - about 20 of them - sip and munch appreciatively while talking know-ledgeably about 18th-century art and architecture. Faintly bemused, I listen to the chat, which is accompanied by the gentle rustle of worn waxed jackets and the faint smell of mothballs.

Who are my companions? A group of middle-aged architecture enthusiasts on a day trip to a country house, perhaps? No. Despite the substantial amounts of tweed, lambswool and red corduroy on display, they are all in their mid-twenties. Styling themselves the Young Georgians, they spend their spare time not in bars or clubs, but travelling around Britain in search of some of our finest 18th-century country houses.

The aim of the organisation - an offshoot of the Georgian Group, a charity that campaigns for the country’s architectural heritage - is to look at, learn about and come to appreciate the architecture of the period - or “not to make country houses seem starchy,” explains Oliver Gerrish, 27, the chairman, who runs his own art gallery in Notting Hill, west London, and is training to become an opera singer.

“A lot of it is just good fun and rushing around the countryside and getting out of town,” he says. “There’s always a mix of people.” Some, he adds, are passionate about art or architecture; others are just there for fun. “But if you’re bored by old buildings or chat about old buildings,” he concedes, “it’s not really the best thing.”

Many of the members have been architecture aficionados all their lives; one earnest young man recalls how he used to drag his parents round National Trust properties at the age of six. Others, such as Henry Conway, the fashion-loving son of the disgraced Tory MP Derek Conway, are more flamboyant. Most have joined via friends of friends. The atmosphere is jolly and country-house-partyish - unsurprising given that the overwhelming majority of Young Georgians are, to put it bluntly, posh.

There is Toby, 27, who is a banker, drives a Jaguar and inquires whether I have “come up from town” (they all call London “town”). Camilla, 24, a pale blonde in pink Hunter wellies, is a book restorer who has “always lived in Georgian houses” and likes the fact that nobody in the Young Georgians talks about what’s happening in the City; Adrian, 26, an actor, joined because he had purchased a “shell” of a Georgian townhouse and wanted to know what to do with it. Then there’s Martin, 27, the parent-dragger.

I have joined the group midway through their visit. They spent the previous day at Carnfield Hall, the home of James Cartland (a prominent collector of memorabilia that includes a 200-year-old stuffed canary), and Casterne Hall, an 18th-century “gentleman’s seat” that has been used as a set for a number of television films, including Jane Eyre, The Hound of the Baskervilles and Far from the Madding Crowd.

The previous night was spent in the Derbyshire village of Bonsall, where they were put up in various local houses and B&Bs – and a rather less highbrow kind of entertainment took place, in the form of a karaoke night in the local pub, where, I am told, one Young Georgian performed a spirited rendition of Britney Spears’s Hit Me, Baby, One More Time.

This is discussed with great merriment at lunchtime (a hearty affair in a local cafe), although the conversation swiftly returns to more erudite matters. Camilla denounces the work of Damien Hirst, with a sneer, as “not art”. Martin expounds at length on the beauty and practicality of Georgian arte-facts, and the fact that a Sheraton chair or a Royal Worcester tea cup is just as practical and easy to use as modern items. (Up to a point - just try putting a Royal Worcester tea cup in the dishwasher. ) Postlunch, everyone repairs to a draughty room lined with photographs of Georgian barns, some in a tumbledown state, others a little smarter. They show the work of Lizzie Stoppard, who has taken it upon herself to restore some of the 115 or so of them around the village. Stoppard is passionate about what she does - and, though it is a far cry from the country houses the group are used to, they respond politely and ask questions. When we go to look at some of the barns, they continue to show enthusiasm, although there is more excitement about a pair of horses in an adjoining field. The group poses obligingly for a photograph, then it’s time for tea and cakes, again in the café, before everyone prepares to head back to “town”.

Gerrish proclaims himself pleased with the weekend. It is the first overnight trip he has organised - usually, they are day trips, often to a house a member has suggested or where someone knows someone. So, does membership, which costs £20 a year, require intimate knowledge of the family trees of England’s remaining landed gentry?

Not at all, Gerrish assures me - many members simply suggest places they would like to visit, and most country-house owners are more than happy to have people round. “People do worry about the next generation,” he says. “And if young people see these places as starchy old mansions, they could fall into ruin. We want to celebrate the heritage of the houses that are standing - and make people aware of the threat to them.”

Gerrish has a point. Despite my reservations, I have enjoyed the weekend. My knowledge of Georgian architecture has increased considerably - and, for all their peculiarities, I have met some charming people. Proof of this comes the next day: logging on to Facebook, I have three friend requests from Young Georgian members, and, embarrassingly, I feature in several of their photographs. What am I wearing? A Barbour and green wellies, of course, both of which are mine. Perhaps even I am a Young Georgian at heart.

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