Love thy neighbour: Margo Leadbetter enjoyed the sadomasochistic sport of Surbiton social climbing

Every now and again, fashion alights on the old cliché of the bourgeoise woman as a focal point. Generally, it means primness, plenty of pearls, maybe a bit of free-falling georgette and a pussy-cat bow. It's a look Miuccia Prada loves, hence the rest of the fashion world does too. It smacks of old Saint Laurent, a bit Belle de Jour. All terribly French. But personally, I can't see those bourgeoise stalwarts without thinking of Margo Leadbetter in The Good Life – opening the style up to a very different interpretation indeed.

Margo's fashion sense may be the BBC Costume Department's finest contribution to style. Forget the am-dram, drab Empire lines of Pride and Prejudice, or even the dodgy early-Nineties reimagined flapper frocks in The House of Eliott (although I do harbour a deep affection for those). Margo wore geometric prints, furs, flowing hostess gowns occasionally matched with a turban. Penelope Keith, who played her, stood five-foot-10 tall – add the towering platforms that characterised the series' run from 1975 to 1978, and you have a true-to-life glamazon.

The Good Life and Belle de Jour aren't that different, really. (Bear with me.) While Séverine poured her passion into sadomasochistic sexual encounters, Margo channelled it into the equally sadomasochistic sport of Surbiton social climbing. Both require one hell of a wardrobe – an expensive one, apparently. Keith and Rita Reekie, the series' costume designer, trawled Regent Street and Harrods for Margo's costumes.

Tom and Barbara wore the same clothes throughout, so Reekie spent the majority of her budget on Margo. And it shows. There are chiffon kaftans that recall Jean Varon, neat tailored suits with matching hats that put one in mind of Karl Lagerfeld's early days at Chloé, and a huge dash of YSL. When Margo leaves Jerry over his failure to fork out for a musical spinning-wheel, she does so in a fox-trimmed ode to Saint Laurent's 1976 Russian collection, with matching fur ushanka.

I'm not completely insane. Others share my fixation. "I adore Penelope Keith's character from The Good Life," says Giles Deacon, a designer who is no stranger to a pussy-cat bow himself. "Her outfits still look great now. A favourite of mine is a bright yellow three-quarter length A-line shift, that looks like it came straight from Nina Ricci."

Nina Ricci didn't give me a Margo vibe this season, nor Prada – far too rumpled and unkempt for Margo's pin-neat perfectionism. Marco Zanini's Rochas collection, peopled with silk-crepe lounging pyjamas, capacious camel coats and fur-cuffed cashmere cardigans, seemed perfect, as did Deacon's pre-collection with its bow-necked tent dresses and slender maxi-skirts.

I suppose this is more a catalogue of my obsession with Margo – and my ability to spot her look lurking in the most unlikely of places. I doubt Miuccia has been watching Margo. But I like to imagine she does.

Alexander Fury is Fashion Editor of 'The Independent'