Any colour as long as it's red

When the Lloyd's of London building celebrated its 25th anniversary this week, the architect to whom its groundbreaking design is ascribed was there to mark the occasion.

But as Lord Rogers rode one of the famous glass lifts that rise outside its 14 floors, he was briefly upstaged by his business partner, Mike Davies – or, more precisely, by his outfit. Rogers has a taste for lime green or magenta shirts, but Davies's personal style choices are more radical: he wears red, and only red. His shirts are red. His suits are red. His shoes are red. His belt, his watch, his mobile phone holster, even the elastic band he uses to tie his ponytail: all red.

He sketches his designs in red ink, with a red pen. He drives a 17-year-old red Jaguar, with customised red leather interior. An accomplished amateur astronomer, he owns more than 20 red telescopes. "I remember walking around Lloyd's when we were designing the building," he says, "and I must have cost them 20 or 30 grand every time I came through the office, because they all stopped trading to look at me! In fact, I was in the same outfit as they were: I had polished leather shoes, suit, tie, shirt. The only difference was 4,000 angstroms in the colour spectrum."

As a young man, Davies preferred purple, but when he joined Rogers to work on the design for the Pompidou Centre in Paris, he learned that it was the colour code for the Parisian gay community. His bottom was pinched on the Metro one too many times, so he switched. "It's simple," he says of his single-colour philosophy. "The complications of dress code, of matching everything in the morning, disappear completely." If he were to switch again, he would choose yellow. "But if I changed now, it would break me financially."

He may be an extreme case, but Davies is not the only architect with an idiosyncratic approach to fashion. Frank Lloyd Wright always sported a cape. Sir James Stirling, after whom the annual architecture prize is named, wore blue shirts, purple socks and Hush Puppies. Daniel Libeskind is never without his cowboy boots.

Davies was born in Wales, and decided to be an architect after seeing the Skylon at the Festival of Britain in 1951, when he was nine. He studied with Rogers at the Architectural Association in London during the 1960s. He recalls: "The last thing anyone wanted to design was a building. We were all into loose-fit, gypsy living."

Accordingly, he moved to California at the height of the hippie movement. An early convert to alternative energy, he built wind turbines and solar collectors when they were avant-garde. He co-founded Chrysalis, a multi-disciplinary practice dedicated to building lightweight structures, such as the Pepsi-Cola pavilion at Expo '70, which was then the biggest inflated mirror-dome in the world. He also ran a "video van" in the tough Watts district of LA. "We were teaching black kids to use video," he says, "which was almost unheard of."

After returning to Europe to work on the Pompidou Centre, in 1977 he helped to establish the Richard Rogers Partnership. Design expert Stephen Bayley says: "The four original partners were brilliantly complementary: Rogers, the suave, cosmopolitan frontman; Marco Goldschmied, who did the money; John Young, who was bonkers about detail and precision. Then there was Mike, who brought the Sixties California New Ageism; Mike was the visionary."

Davies was project director on two of the firm's most high-profile endeavours, Heathrow Terminal Five and the Millennium Dome. Like the Lloyd's building, both were controversial, but are now beloved. Davies says he's looking forward to watching international tennis at the O2, as the Dome is now known, next week. The practice was recently given planning approval to construct a "skywalk" over the top of the structure. "What drives the thinking on almost all our projects is flexibility, growth and change," Davies says. "Inherent flexibility is part of the formula. As Richard says, you could turn Lloyd's into a fishmarket without any problem."

The firm – now called Rogers Stirk Harbour + Partners – is again working in Paris, on two grand-scale urban design projects. Rogers and Davies are the only remaining original partners, though they share responsibility with a further eight directors. The founding principles of teamwork remain intact. "Every Monday morning," says Davies, "we get together and work as a group, so that all the talents of the different directors are brought to bear."

The same mindset applies to Davies's red fixation. "I don't impose it on anybody else," he says. "Only on myself. It's a liberal, not a fascist decision. I don't have a red house and a red wife." His wife, as it happens, is a performance artist, and he also paints and sculpts. "I've become an art object," he says. "Wearing red challenges orthodoxies: our firm has never been orthodox, so it's in the spirit of what we do."

Status Symbol: How to wear it

From the cassocks of Catholic cardinals to the cape of Superman, red epitomises power. Put simply, it commands respect.

And, unlike other bold colours, it retains a sense of flamboyance, which goes some way to explaining why it proves popular with designers. At the autumn/winter menswear shows Raf Simons' red smock coat was nothing if not theatrical, while the red tailored suits at Dolce & Gabbana proved a master class in how to impress.

What about the rest of us who don't have the nerve to dress like Santa Claus? When adding colour to our daily wardrobe, the devil is in the detail. Stick to grey flannel suits but add a splash of red with a tie or a pocket square. Approach red jackets with trepidation, unless, of course, you're applying for a job at Butlins.

Lee Holmes