Helen Green has designed the interior of luxury yachts, English country houses and the Coral Reef Club hotel in Barbados. Her calm, sophisticated London townhouse is another fine example of her versatility and vision.       What is the architectural style of your home? Early Victorian. How would you describe your interior? Modern classic. The contemporary furniture blends well with the few antiques. I've gone for neutrals on the walls, although I used a beautiful blue for the staircase. What did you dislike most about your home when you first moved in? We hated everything. The interior hadn't been touched since 1935 and needed modernisation – but it meant it was an interior designer's dream. Which is you favourite room and why? The kitchen/dining room. It's one big integrated space with a plasma-screen TV fitted with surround sound and a kitchen area that looks out over the garden. Have you had any decorating disasters? No, none that I can remember. We literally planned everything down to the last lampshade before we began work. I think planning is the best way to avoid making mistakes. Which paints have you used? Paint and Papers Library's architectural range: Stone, Sand and Taupe are favourites of mine. The blue on the staircase is Leyland's F28 Mist. Which fabrics have you used? The drawing rooms sofas are upholstered in Sahco Hesslein's Lavello in both blue-grey and muddy chocolate. The curtains are made from Calque by Nobilis, which is a light voile-like fabric. I backed and interlined them and now they hang perfectly. I chose a grey-taupe shade, as it is shot with all the colours I've used in the rest of the room. What about the furniture? We commissioned most of it, such as the sofas and chairs in the drawing room and the dining table. If I can't find something I like, I'll design it myself and then get one of the workshops I work with around the country to make it for me. Which plants have you used in the garden? Sculptural box hedging, bamboo as a backdrop and hydrangeas, silver birch and camellias to soften the overall effect. Which item couldn't you live without? My dining-room table, which I designed myself. It's made from polished macassar ebony veneer, which has amazing gold streaks in it. Do you own any tasteless objects? Lots! I keep them for sentimental reasons, though I have to say they're not on display. Do you have any decorating rules? You should always trust your instincts and never compromise. Which three words best describe your home? Ultimate urban abode.