He's the young British designer who took the handbag world by storm. Carola Long catches up with Stuart Vevers in his new kingdom at the Spanish luxury label Loewe

Though it's February, the sky in Madrid is bright blue and the sun is gently beaming into Stuart Vevers' office, gilding the soft, suede Loewe bowling bag he is holding in a halo of light. The golden boy of accessories has been installed here as creative director of Loewe since January 2008, after leaving Mulberry where he made his name. Vevers is a man who knows, perhaps better than anyone, how to create bag envy, but after seeing his new workspace – all big windows with a view of the city, architect-style tables covered in neat drawings and even a chic rooftop garden lined with miniature trees in pots – I am struck by bag-designer envy. Were he only over here on a less glamorous mission – to redesign the uniform for one of Spain's supermarket chains, say – this office would still be worth upping sticks for. "I'm very lucky, it's very nice," says the amiable British designer, whose heavy black glasses and diffident manner give him a slightly geeky air.

However, luck doesn't really come into Vevers' appointment at Loewe – the benefits to both parties are obvious. After leaving Mulberry in July 2007, where he made his name, he joined Loewe, or "low-ay-vay", and found himself with 163 years of history and expertise to play with. Established in 1846 by a group of artisans making small leather goods and later joined by a designer called Enrique Loewe Roessberg, the house, now owned by LVMH, has a strong reputation for its leather accessories, and to a lesser extent its clothes, which have been designed in the past by names such as Karl Lagerfeld and Giorgio Armani. It is a national institution in Spain as the country's only luxury label and supplier of leather goods to the royal family, while from the mid-Forties to the Seventies the flagship store was famed for its exotic and surreal window displays. In Vevers the house found a designer who respects this tradition. He says, with what certainly seems like genuine reverence rather than diplomacy, "Everything I do has a sense of Loewe about it. I want to work with the brand rather than fight against it. I don't want to create something new, I want to take what I feel the label stands for and make it relevant to right now."

Loewe's star shot up through fashion's firmament when Vevers came on board; and there is already a buzz around the current collection. After all, he had turned Mulberry from a label synonymous with urban Sloanes and horsey Hampshire types, to a more cosmopolitan name coveted by young, trend-conscious women. His designs were responsible for fuelling It-bag mania, as consumers who might consider themselves too rational to succumb to obvious branding or logos were seduced by Vevers' contemporary designs.

However, the thoughtful 35-year-old isn't at Loewe just to design handbags – when we meet he is in the middle of finishing the autumn/winter 2009 ready-to-wear line that appeared in his first Paris catwalk show in March. Vevers might have earnt his reputation as an accessories designer, but he trained in fashion design at Westminster College, graduating in 1996. He had his heart set on working for Calvin Klein, and ended up in their accessories department by chance before going on to work for Bottega Veneta, Givenchy, Louis Vuitton and Mulberry. Vevers says, "I think the highlights of my career have involved accessories, whether it's commercial success or celebrity endorsement or awards," but he regards a move into womenswear as a natural one. Certainly he's not alone: Gucci designer Frida Giannini has an accessories background, as do the new joint creative directors at Valentino, Maria Grazia Chiuri and Pier Paolo Piccioli – after all, the money is in bags, shoes and sunglasses. Vevers says, "I never wanted to be pigeonholed, and I guess I have been in some ways, but I always thought that a designer is a designer and if someone asked me to create a vase or a teacup tomorrow, well then it's the same process."

With three weeks to go before the show, Vevers and his team have created about half the ready-to-wear collection. The mood boards, swatches of coloured leather, fabric, details and sketches are testament to a work in progress; albeit an impressively organised one. The slightly shy Vevers says he doesn't want his desk photographed because he thinks it looks messy, offering an insight into his meticulous nature. "There's so many ideas and references in one collection, you're constantly adding to it up until the last minute. A necklace becomes a belt, becomes a hat." Before the show the design team will set up a small, provisional atelier inside the showroom in Paris so that they can perfect everything at the last minute, and even create an entirely new look if necessary.

Vevers describes the collection as, "a provocative take on the bourgeois look. It's about pushing the boundaries

of what a classical leather-goods house like Loewe is". Inspirations pinned to boards include pictures of Catherine Deneuve in Belle de Jour, the perfect example of the "twisted bourgeois thing". The show, in the grand marble interior of the Université Paris Descartes in Paris, certainly evokes the "rich, grown-up, elegant woman with an edge", that the designer wanted to capture. Shift dresses with punched Madrid 1846 logos, in black leather and Paprika suede, prom dresses in suede and calf hair with scalloped detailing, and cropped leather trousers and biker jackets, made the most of the house's leatherwork tradition to evoke a wealthy, sexually self-aware woman. Just as YSL showed a Parisian take on modern sexuality, so this was a more baroque, Spanish one. Vevers describes the Spanish look as "quite bourgeois, heavy and rich. You see more red lipstick than any other city and it's more sexy. It's about looking good all day." Strong but sensual wool shift dresses with tiers of scallops, rivets, punched ticker-tape-like sections and studs, Eighties-inspired leather trenches and box pleat calf-hair skirts felt luxe but modern. And then, of course, there were the bags – soft rectangular takes on bowling bags in black leather, slouchy satchels in yellow suede and orange or brown leather, and shoulder bags in teal ostrich – plus wide, knee-high leather boots. An extra dose of credibility, as well as expertise, came via Katie Grand, who styled the show. She is part of Vevers' fashion gang, which includes Giles Deacon and Luella Bartley (to whose second child he is godfather).

Vevers couched the aesthetic of the show as "provocative classicism" – a description that could be applied to his whole ethos at the house. It also informs his approach to weathering the recession; he doesn't buy into the theory that straitened times mean "a return to pure classicism". He explains, "people aren't going to be satisfied with that – just because something is an investment it doesn't suddenly mean it's boring. Why can't a pink bag be an investment if that's what gets your heart racing? It's like ..." he pauses, looking out of the window and up at a statue of a man on horseback as if asking him for an appropriate metaphor. "It's that thing of ... if you've been on a diet for three months and you've been really good, really careful, what do you blow the diet on? It's not going to be an extra piece of dry toast. It'll be a big cream cake that's beautiful and exciting."

Vevers' idea of what constitutes a big, exciting cream-cake of a bag is something with "that sense of special. It's really important that, say, you open a tote and the lining is a beautiful colour and the practicality has been considered, there are extra zips, it's functional. Since I've been at Loewe the investment has gone into the craftsmanship and the materials rather than obvious bits and pieces like the hardware." He grabs a soft, tan-suede Amazonia bag with an oversized darker brown symbol on the side and starts to plump it excitedly, like a pillow. He explains, enthusiastically, how it's "completely unlined ... which breaks down the structure ... the design has been fiddled with over the years and I've taken it back to what it was ... not every house would be able to do that because they don't have the skills." Details such as removing the lining from a bag do not sound hard to adjust, but Vevers insists that "it takes a designer and a technical person hours and hours to make that work well. We prepare about 40 bags for a show and it literally takes ages. We were here until 2am last night to do our first launch of 10 bags."

During the build-up to the show Vevers is at the leather factory on the outskirts of the city "all day every day". All the prototypes or "show bags" are made there, which he says enables him to get really close to the product as it is made, "you are literally the person saying, 'Make it a bit heavier, make that stitching a bit smaller'," he says. "You can try a lining in a spontaneous colour combination and if it doesn't work you are there and you can change it. That doesn't work if your prototype factory is in Asia."

The factory-cum-atelier where the show bags, along with the ready-to-wear samples, are produced gives a fascinating insight into how much work goes into creating bags and ready to wear. Vevers' sketches for the clothes are given to a "modeliste" to interpret, who will create a prototype in a rough fabric, sew it, pin it, make a pattern, then send it to another factory to make another prototype, which is then fitted on a model to check that it reflects what Vevers had in mind. After it has been machine sewn, buttons and embellishments are then added by hand. In the accessories section, where rolls of leather as soft as melted chocolate in shades of mustard, raspberry, tan and forest green sit in precarious piles; hand drawing is still favoured over computers. Vevers' drawings are recreated in a thick grey felt version which can take two days to make, after which he draws on changes in black marker. A genuine sample can then take three to four days to make by artisans who may have over 40 or 50 years of experience. One tells me that the difference between Vevers and his predecessors is that he adds more details spontaneously, and plays with colours and textures until it comes to life.

Part of the atelier is also devoted to making up so-called VIP orders, recent examples of which were for Amber Valletta and Victoria Beckham. Beckham, a former Madrid resident, has been spotted toting her own bespoke Loewe Calle bag. Vevers met her through a friend, and created a bag to her personal specifications. He doesn't believe in "blindly sending things out to celebrities. It's not very cool and I didn't do it at Mulberry either. I prefer to have a more personal approach."

Vevers believes that the economic climate may send people back to the houses "that have real know-how in a particular field ... where you think, 'They know what they're doing'." After the show is over in Paris and the models are slipping off the leather trenches and dresses backstage, Vevers allows himself the broad but exhausted smile of someone who was up until 3am but knows just what he is doing.