Who'd live in an eco-house like this?

There have been more than a few surreal moments at the Lower Mill Estate in recent times which might go some way to illustrating just how elite this community is.

There was the occasion that Kylie Minogue decided to start singing in one of the private spa's swimming pools. Then, there was the morning when residents of the nature reserve deep in the Cotswolds bumped into Brad Pitt and Angelina Jolie in the village shop. And then, there was the time that dancer Darcey Bussell handed out the prizes for the sack race at the summer fayre.

Any one of those incidents would have been retold countlessly, in gossipy whispers in any other village, but this is Lower Mill Estate - eco-estate extraordinaire and Britain's most exclusive community. And no, "It's not the type of place for poor people on the breadline," declares Jeremy Paxton, a former professional water-skier turned publisher who bought the 550-acre estate 12 years ago.

Paxton, 48, originally bought Lower Mill to live there himself, but after spotting the potential for an exclusive private community where the environment and sustainability would play as big a part as the residents, he applied for planning permission to build 577 homes.

Since permission was granted in 1998, 214 homes have been built on the idyllic estate. Amazingly, the village has remained a relatively well-kept secret until earlier this week when it emerged that The Orchid, a revolutionary eco-house modelled on shape of a Bee Orchid has just been sold for £7.2 million – a world record for a UK country home.

The identity of the buyer is a closely guarded secret which Paxton will not reveal. He also won't reveal the names of any of the other celebrities that own a large chunk of the estate's 214 homes, though he says he has turned a lot of footballers and their wives down.

"The reason we get so many celebrities and well-known people coming here is because one of the main reasons they come is for the privacy," he explains. "Some of the names do get out, but they don't come from me. If I start telling the press who I have living here then I'm going to lose business."

But Lower Mill's residents are not all famous. Those who reside here include lawyers, bankers, writers and photographers from across Europe and the USA. And as we wander along the winding grassy paths, listening to birds twitter in the dappled spring sunshine, Paxton declares that they all get along handsomely.

Each who lives here has bought their house off-plan and each home is built to order, meaning it takes at least 18 months between when the home is purchased and the time at which the buyer can move in. The Orchid, which it is hoped will produce more energy than it uses, with an underground heat pump, geothermal heating and cooling, rainwater and solar and wind power, will take three years to build.

"The community is really thriving and everyone seems to get along well together," smiles Paxton. "Lots of the famous people who buy here ask for agreements in their contracts which state that we won't tell people they are here. And similarly, I put agreements in the leasehold contracts of all the residents which basically say that they aren't allowed to gossip about who they have seen here."

It is the first sniff that perhaps such an idyllic lifestyle comes at a price. Because no gossiping is not the only rule here. If you want to live in Britain's most exclusive resort, you have to toe the line and prepare to follow an extensive list of dos and don'ts.

Firstly, forget about holding your Stag or Hen 'do here, because they aren't allowed (cocktail parties are). Residents are not allowed to hang their washing in their garden – they can either use a tumble drier (frankly not that ecologically friendly) or take their clothes to the on-site launderette. No 'For Sale' signs are allowed, ditto no television aerials or unsightly satellite dishes. Residents must not engage in activity that will be a nuisance to you neighbour.

Even more irritatingly, the main rule in this rural idyll is you can't live here all year round - and not at all in January. The reason: residents must adhere to their environmental responsibilities. Houses can only be built if they respect the wildlife. Certain areas are off limits at certain times of the year, and in particular in January, to allow birds to nest and other wildlife to breed. Any homes bought on the Lower Mill Estate must be your second home.

"We have had to turn some pretty famous people away because we didn't like the type of house they were planning to build," says Paxton. "And we will walk away from the transaction if we are not happy, it doesn't matter how rich or famous people are, we don't need money because this place is completely debt free, we aren't under any financial pressure to bow to people's demands if we're not happy.

"There was one instance a few months ago where a celebrity, who had a particularly high profile in all the papers at the time, wanted to do a deal over the phone and we told him 'no'. He warned us that we risked losing the deal if we didn't let him buy over the phone and we told him that we were prepared to take that risk. We insist that people who want to buy come here so that they can see what we are about and vice versa."

Paxton refuses to reveal the name of that particularly stubborn client, he does concede that "We must have got through to him because he came to visit and ended up buying."

While Paxton is at pains to protect the identities of his well-known clientele, however he has no such qualms about revealing who he doesn't want on the estate. "We've got no footballers," he tells me. I ask if that's the way he would like it to stay. "Yes," he says.

After our tour of the £6 million spa's facilities: the swimming pools (one is a natural water lake), the gym, the tennis courts, the theatre and the library - all of which are free for the residents to use - we head out to view some houses on the estate. The first, a four-bedroom house sold for £500,000 – the cheapest house on the estate. With three floors, two balconies and surrounded by a moat, even in its raw state, it is clear this will be a home of the utmost luxury.

But, to my surprise, Jeremy says that The Orchid, the home that has sold for £7.2 million, will be roughly the same size as the house we are standing in – the house that cost £6.7 million less.

"It's all about the detail," he says. "The houses don't differ too much in size, it's the specifics you ask for that will start to send the price soaring. The Orchid, for example, will have an art studio inside and an Olympic-size swimming pool outside. Two houses could be identical on the outside, but could differ by millions of pounds in cost because of what is inside them. But that's what we pride ourselves on. We offer the ultimate in bespoke housing and will give the buyer exactly what they want right down to the types of handles they want on their doors.

"Also, once people move in, our service is like a five star hotel service in your own home. We will do anything that someone asks for. We had one guy who wanted to fly to France in a private jet to go for lunch and we sorted that for him. But at the other end of the scale we get requests to fix punctures on people's bikes. It's all about perfection, and that stems from my own personal quest for perfection."

As we leave the semi-built house, I get an idea of Paxton's vision of perfection. He takes me to his own grand home on the edge of the estate. It is as spectacular as you'd imagine, complete with balconies and swimming pools. Then, we head to his office for lunch. Across a wooden footbridge the office sits alone in the middle of a man-made lake. The room is bigger than my flat.

Over lunch, a pasta salad with pesto handmade by a local chef and sold in the village shop, Paxton tells me about how big a part the environment plays in his vision for the estate. Of the 550 acres, which includes three rivers and seven lakes, two-thirds have been set aside as a nature reserve which is home to more than 3,000 species of animals, insects and birds including beavers, which were reintroduced to Britain by Paxton.

Those two-thirds of land will never be built on "I've made legal assurances of that,"he tells me. "I've made sure that even after my death no one can ever build on those bits of land and it's really important that that is the case because I think it is one of our biggest attractions. Not only to the people like coming here because it is right out of the way and no one will bother them, but for the money they pay they are getting a fabulous home and access to a 550-acre estate, with loads of wildlife, for a fraction of the price. It really is a great place to live. I've lived here for 12 years and I love it – I still find bits of the place that I've never seen before."

At the village shop where Mars Bars and Walkers Crisps jostle for space alongside local meats and cheeses from farms across the Cotswolds, Paxton tells me that his plans for Lower Mill are far from at an end.

He has spent £40 million on the project so far and estimates that will rise to £250 million by the time he stops working on it. But the huge expense has clearly been worth it. He make a profit every year and the place is undoubtedly thriving: "We've actually got more residents here than a lot of the villages nearby and we are doing better than them too, all the local shops in villages round her are closing, but ours made a £36,000 profit last year." I point out that many of the local shops aren't frequented by millionaires and celebrities "Yeah, that's a fair point," he concedes.

But despite the incredible success he has made of the community, Paxton is already talking about his next plan: "I want to build a pub here. Not just any pub, a recycled pub. I'm going to buy a pub that closes down and rebuild it here, brick by brick. It's going to be a proper boozer too, with great food and drink and a darts team and a pool team."

Driving back home, I wonder what the locals of The Bakers Arms, the pub in nearby Somerford Keynes, will make of an opposition darts team featuring Kylie Minogue, Brad Pitt and Angelina Jolie? And then, I wonder who would win.