Jeff Griffin is sussed. He's his own boss who's been running his own menswear label, Griffin since 1993. Last year, a Griffin shop (dubbed a 'playground' by designers El Ultimo Grito) opened on London's Portobello Road, and later this year another will open in Tokyo. In addition to designing Griffin, Jeff and his team are in-demand consultants with a rock solid rep from working with brands including Mandarina Duck and Sony. He recently moved to the country and when he's not travelling, he's hanging out with his kids and walking up hills near Stonehenge.

Griffin clothes are experimental, humorous and hardy. There are moulded hoods, adjustable features, upside down coats, travel pods and sleeping bag coats. Inspirations have included Hugh Hefner, gypsies and geometry. It's ostensibly a menswear label, but women also wear it. Griffin has grown through word-of-mouth, and some customers behave like strange converts obsessively emailing Jeff or travelling thousands of miles just to visit the shop.

The label constantly breaks commercial rules, doing things like incorporating linings which cost more than outer fabrics. "Things like that which you would never do for other companies, we can do for Griffin," says a ruddy faced Jeff with genuine pride.

As a consultancy, Griffin has no problem telling other fashion companies what they should be doing, but they're less clear about their own mission. "When you're doing corporations it's all about positioning in the market place and you graph it all up, where they are positioned, who are they aiming at ... and with us y'know we're not cheap, but we're not massively expensive. All we know is quite a lot of people wear it and a lot of people like it .. it's still not a simple message."

Griffin doesn't launch two completely new collections each year, instead it creates key garments - like the legendary sleeping bag coat - and refines them across a few seasons. It's the antithesis of mainstream fashion's trendmongering. As Jeff sees it: "Once you have developed something why get rid of it? And you can always improve things - the sleeping bag coat moved on and then became the Travel Pod, which was a bit more futuristic."

For a while Griffin was associated with techno fabrics, but these days the team enjoys using natural materials and experimenting with dyes and washes (and Jeff says he got sick of the noise made by all those paper-type fabrics!) Summer Solstice, the spring summer 2002 collection features treated, roughed-up cottons with lots of embellishments. The pieces look distressed and dishevelled, but everything has been produced to the highest spec by an Italian manufacturer. Apparently, it took a lot of work to convince the quality-conscious Italians that this 'falling apart' look was exactly what Griffin wanted.

There is no fixed Griffin logo and the name never appears on the outside of garments. Last season's If You Want To Get Ahead Get A Horse collection featured equine imagery and was launched by pulling an enormous plastic horse down the Portobello Road. The horse reference Jeff says was "taking the mickey out of Ralph Lauren." This season's logo is a graffiti-style bird in flight along with a love heart. Previous gems include a collection which pays homage to Norfolk and one called Mat Hates The Sea. Each collection is imbued with a sort of Jacob's cream crackers, bus queue conversations, socks and sandals Englishness.

The design process is collaborative. As Jeff explains: "I never wanted it to be Jeff Griffin's collection, and I never wanted to be too precious about it, I wanted as many people to be involved as possible, when we bring people in it's not just the design, it's the shop the shoots, the installations." Cash from the consultancy side of the business is invested into the clothing label which gives Jeff freedom and flexibility.

Griffin was one of the first UK fashion labels to go online - www.griffin-studio.co.uk - in 1998 it abandoned the traditional catwalk show and presented a web collection instead. Since then, the website has been an important part of the label, but collections have never been sold online. Instead people use the site to track down pieces they are trying to find and to talk to Griffin.

"I suppose people are so used to corporations that when they get a company like us where they can actually talk to us, sometimes they go a bit over the top. People are really surprised when I answer their emails asking about buying a pair of trousers."

It's this no logo, fluid thinking, amuse ourselves approach that makes Griffin different. While other fashion designers are desperately trying to develop international brands, Griffin's focus is on making great clothes that tell stories and evolve. As Jeff sees it, the corporate game ain't for them.

"Calvin Klein advertises so much, but they don't really give much to the staff really to help them tell the story, whereas we don't advertise at all but you come in to the shop and talk to Remi and you'll be here for two hours.."

In some ways, it's easier for Jeff to say what the label isn't than what it is. Although creating clothes is its core activity there's so much more going on - art projects, consultancy, retail, product design and plenty of passionate piss taking. When I ask whether Jeff considers Griffin to be a brand he admits: "We've always been a bit confused about it. We can do consultancy for other people and it seems very clear, very simple and you can carve them out a direction and when it comes to ours we've had this conversation for the last ten years - are we fashion or are we not fashion? OK, we don't want to be fashion, so we'll say we're not fashion but I was trained as fashion designer so it obviously is fashion.. ..we've done suits, we've done jeans, we've done sculpture so where do we really fit and is it a clear message? It's not a clear message. Should it be a clear message? It should, so that's why it's probably interesting that it's not a clear message."

While Jeff has no time for "fashion people who work on very mediocre products" he's great respect for contemporaries including Galliano ("he's a bit of a god because he does his thing and it's his own ship"), Commes des Garcon, Silas and Bathing Ape: "I am really into what they stand for.. and I love their obsession. I don't think their clothes are very good, but I have got their dolls, I've got their stickers and everything that surrounds the brand I love. I think their shop is looks amazing and I think they're fantastic, they're from music and they've their little obsession with the apes and I fucking love it, it's fantastic."

Griffin collections are splattered with military references, and Jeff makes no apology for his love of army land rovers, old war films and conflict clothing. He drools over the aesthetic qualities of guns: "You can be really anti the gun, but as soon as you hold one it's a lovely piece of machinery.. it's metal it's cold it's aggressive it's masculine." The main attraction of military design is that "it always looks genuine, it always looks solid, it always looks tough" and likens his approach to "how John Lennon used to wear military fatigues, I suppose it's a reference point I love."

As well as a new Tokyo shop, 2002 should see a few other Griffin projects. The first Griffin car is almost complete - it has a space frame and a Land Rover engine and despite its off-road capabilities, Jeff sees it as an urban vehicle which could go even into production. He's also hoping to buy a forest, preferably with its own military bunker (he loves the contrast of concrete and wood) and offer Griffin adventure holidays. "Forests are fantastic," he says with a big smile.

• The Griffin Concept Store is at 297 Portobello Road, London W11.
• The collection is available from Harvey Nichols, Jones, Cruise and Urban Outfitters in the UK.
• For international stockist enquiries email stockists@griffin-studio.com.