Shoes have legs. Clothes, on the other hand, are unable to stand tall without assistance: without a hanger, mannequin or person inside they sag and flop to the floor. Shoes, however, are built for autonomy - "built" being the operative word.

"Shoes are three-dimensional structures where functionality is crucial; in many respects they are a microcosm of a building," explains Sally Mackereth, a partner in award-winning London-based architects Wells-Mackereth, whose projects have included Pringle stores in Bond Street and Sloane Street.

"My favourite shoes are Hermès," she says, "wedges that comprise of a piece of wood and a single piece of leather - fabulous in terms of both plan and elevation.

"Shoes and buildings can also take you on a journey," Mackereth adds. "When you design a staircase, for example, the shallowness of each step changes the way people move through the space. It is the same when it comes to the proportions of a shoe."

Bermondsey-based company United Nude is a living example of the synergy that exists between footwear and architecture. Founded by Dutch architect Rem D Koolhaas (the nephew of architect Rem Koolhaas) and Galahad Clark (scion of the Somerset-based shoe company), United Nude was built on a single, ultra modern shoe that offers two heights but dispenses with a traditional heel. The Mobius was released in March 2003 and still figures in the collection. A conceptual shoe, it is constructed from a single strip that is sole, heel, footbed and upper.

"Working with Rem has been eye-opening," says Clark, noting that the Mobius was Koolhaas's final project at architectural school. "The way a concept is researched and developed and then realised in product design is just not present in standard shoe design. I have developed a number of products with Rem. Each time they have used new materials, innovative constructions and elaborate moulds."

Koolhaas is not the only designer who has turned to footwear design after studying architecture. Manolo Blahnik studied literature and architecture at the university of Geneva in the 1960s, while French shoe designer Robert Clergerie was trained as an architect before starting work at Charles Jourdan in 1971 and setting up his eponymous French label in 1981.

And up-and-coming Milan-based shoe designer Max Kibardin, 29, had a grounding in architecture in his native Russia. In 1993 the designer won a scholarship to Bratsk University of Industry where he specialised in economics andmanagement in building constructions. "It was in the early 1990s and there were still a lot of Soviet leftovers, such as powerful, monumental, propagandistic buildings," he explains. "Even if I was interested in architectural history I didn't want to dedicate myself to industrial design and I couldn't imagine how creative contemporary architecture might be and how it could be adapted to a post-Soviet reality."

Ultimately, though, you don't have to have studied architecture to appreciate it or understand its underlying principles. Another relative newcomer, 25-year-old London-based Nicholas Kirkwood, is currently being fêted by Bergdorf Goodman in New York and Harrods in London for his clean, structured lines. Citing sculpture and architecture together with the work by Anish Kapoor and Donald Juddas inspiration, Kirkwood explains he just isn't into "cute", diamante or bows. "Because they are required to support a person's weight, I consider heels to be totally architectural," he says. "But I find stilettos old fashioned, and try to develop heel shapes that are younger and more innovative."

Italian luxury shoe label Sergio Rossi, by contrast, is a stalwart when it comes to stilettos. However, since Edmundo Castillo (who previously had his own New York-based shoe label) was appointed creative director in 2004, he has indulged an interest in architecture. Currently designing the autumn/winter 2006/2007 collection, one of Castillo's favourite styles was inspired by the art nouveau movement.

"Unlike clothes, bags, glasses or other accessories," Castillo says, "a shoe has to be not only functional but must respect many other rules. Metaphorically, it is like building a house that has to stand up. Designing a shoe requires a lot of thinking to be timeless and functional. To refer only to fashion is limiting. You have to consider what women like, their travelling, their favourite decorations, their perfume - everything."