"I think it's about an atmosphere," she says of the spacious interior that houses both men's and women's collections and also homeware and found objects including painstakingly-chosen furniture and books. All British, and predominantly dating back to the mid-20th century - "Ercol, Robert Welch, Anglepoise" - the latter enhance a sense of tightly edited modernity and make up 10 to 15 per cent of overall sales.
"I am very aware that we can't compete with what is happening on the high street," Howell says, "and I think what I've always had to offer is my own taste, my own take on things. It's very personal. I understand that I am known as a British designer and I do love certain British cloths [Harris tweed, Irish linen, to name just two] so I try to give it that identity. Personally, I feel very outside of the fashion scene. I've never really related to it all that much."
Unsurprisingly, with that in mind she studied fine art at Goldsmiths College in London. "I left art school knowing I wouldn't be an artist," she says. "For an artist, everything comes from within. A designer needs something to work with. It's more of a practical approach. I was brought up to think it was important to get a job and to make your own money and I'd always made things."
Howell is one of three sisters: "We all looked forward to being bought our own sewing machines aged around 18."
At that point they took over where their mother left off and crafted their own clothes.
Howell's work as an artist did inform what she chose - and still chooses - to wear (and went on to design, for that matter). "Going to art school you're always in practical clothes, dashing around and getting mucky, wearing jeans, T-shirts, shirts. I always, always wore those sort of things. I do also like a mix of refinement and roughness." And flat shoes: "I wear flat shoes because I walk a lot. I did wear heels, little ones, when I was a teenager but I'm athletic. If I'm dressed up I feel too restricted. It's about a lifestyle, really."
Any decoration is kept to the minimum. "With jewellery I like it to be very simple, so it's more to do with the material itself ..." Howell says.
In her pragmatic and instinctive appropriation of a fundamentally masculine wardrobe, Howell was nothing if not ahead of her time. "I've never felt the need to express femininity in the archetypal feminine way," she says. "When I started out, I had razor-cut hair. I used to get on the bus and people would say: 'Is that a man or a woman?' But it was just ... "She pauses for thought: "One knew what one was and that was it".
In 1970, Howell came across a finely-stitched pinstripe shirt in a jumble sale. She was already busy transforming handmade and painted papier-mache beads into necklaces and bracelets and knitting berets and gloves.
"And then I started making my own shirts, finished with old material and braiding, until I decided I wanted to something a little bit more permanent."
Her business as it is now began with a collection of more shirts for men and, cut smaller, for women, which the visionary buyer Joseph Ettedgui was the first to pick up on.
"I think I was filling a gap, making something contemporary and current in very good quality that wasn't over-designed," Howell says.
She bought fabric from traditional English manufacturers and did everything herself. "I had to bind my fingers with Elastoplast because I was cutting through several layers with scissors." In France, she came across traditional workmen's jackets and re-mastered them. Soon she expanded into trousers and then a raincoat. And so it went. In 1977, and now with her own workshop machinists and pattern cutters, she opened a menswear store in partnership with Ettedgui, housing a complete collection. In 1980, her own stand-alone womenswear boutique followed.
More than 30 years on and Howell heads up a company that, by British fashion standards at least, is quite an empire. She has a womenswear designer, a menswear designer and is responsible for twice-yearly ready-to-wear collections along with the rest of them. Less conventional is the fact that her own approach, wherever possible, has remained just the same.
"When I was doing it all myself, it was never about working on a collection," she says. "It was just one thing, and then another, and another. A collection is something you have to see as a whole but I was always much more keen on finding specialist suppliers of things that inspired me and then working with their product to get what I wanted."
Reach out and touch Howell's grey flannel or corduroy, her linen, cotton and cashmere, and you know that it is the care that has gone into its sourcing that makes it the finest money can buy. Invest in one of her raincoats and trust that she has studied every last detail of its form and function. There may be more to a Margaret Howell collection than there once was: that is a requirement if only for commercial reasons. Her label's heart, though, lies in the classic garments that can be worn and loved for a lifetime and that come, each season, maybe re-coloured or cut in a different weight of fabric. Wide-legged trousers, trench coats, shift dresses, circle skirts, cosy roll-necks, flat leather sandals and moccasins all bear her discreetly beautiful handwriting. It can be seen in everything from the overriding, no-frills and perfectly-proportioned sensibility, to the impeccable finish.
It almost goes without saying that sensibility has spawned more than a few imitators - from the high street to other people's catwalks - but Howell doesn't care.
"There's always been the odd copy," she says, in typically self-deprecating manner, "and of course I'm aware of them, but there's absolutely nothing you can do about it. You just get on with what you do, don't you?"
* Selected Margaret Howell pieces are available in New Zealand from Fabric, ph (09) 366 4528, and Everyday Needs.
