Shop till you're dropped... Moss reaches sell-by date

For three years she was Sir Philip Green's darling. But the model's new Topshop collection is also her last

"It's an event; something you can say you were part of." That was the verdict of a mother and daughter I spoke to in the queue for the first Kate Moss for Topshop collection, back in 2007.

After hours of jostling in a crowd of hyperventilating teenage girls, they insisted she would be worth it.

Three and a half years after the world's most famous model stood in the window of Topshop's Oxford Circus branch for a mere 12 seconds to promote her first ever fashion range – and as she prepares to unveil her last – what has the high-profile partnership done for the fortunes of the model, the mogul – Topshop owner Sir Philip Green – and the crowds who have bought into Brand Moss?

In September, Green cited practical reasons for the demise of the partnership, which has produced 14 collections, and will continue in some form, saying that it, "probably became too overloaded. It wasn't working... we were trying to produce these big collections but it was too difficult and we needed a rethink."

Green denied rumours of an acrimonious parting, saying: "We have discussed it and decided this was the way to go. It isn't a split".

He dismissed as "absolute nonsense" speculation that he was making space for a new queen bee: his daughter Chloe. More likely – given that there should be room for both of them in Arcadia, Green's business empire which announced pre-tax profits of £213.6m last July – is that, much like everything in fashion, Kate Moss's collection had a sell-by date.

Some might argue that it expired some time ago. While it got off to a flying start, causing hysteria and sky-high prices on eBay, enthusiasm and sales have dampened since. If the clothes were still bringing in the bucks, Green would probably have kept it going until Moss was 50 and running an animal sanctuary in Devon. He initially credited her with helping to boost Topshop's profits, calling her a "fantastic ambassador".

Of course, the Moss Effect can't just be measured in direct sales. It also helped generate glamour for a high street store, particularly in the US, where Green and Moss turned out together in New York for the launch of the chain's first American outlet.

Since then, it's hard to gauge how well Moss sells; Topshop says it does not break down figures, but stock no longer flies off shelves. Three years ago you could hardly swing a Topshop carrier bag without hitting a "Kate Moss", now I don't know of anyone itching to buy the new range.

Anyone still keen on Moss can expect more of the same from her last range. Her clothes started out with a vintage feel, moved into a more boyish, beatnik look and have settled – some might say "stuck" – in bohemian rock groupie territory – think Stevie Nicks meets Marianne Faithful.

The range includes bell-sleeved printed dresses, folkish embroidered effects, Paisley and bell sleeves, capes and maxi-dresses and velvet hotpants with a lingerie-like lace trim.

In a bid to shift more stock Moss will return to Topshop's flagship Oxford Circus store on Monday.

Alongside the new designs, Topshop will release 10 of the best-selling pieces since the launch, rather grandly labelling them "Kate Iconic".

Topshop is trying to write its own, glowing obituary for the range, but while the early collections included nice-enough pieces, such as flowered tea dresses, one-shouldered day dresses, tight leather jackets and skinny flared jeans, 14 ranges later they are no longer setting the high street alight.

Moss has always drawn on her own wardrobe, which in turn is full of vintage pieces and designs by the likes of Galliano and McQueen. Given that her own style hasn't changed much in the last few years, neither has her collection. It could be called Kate Moss Déjà Vu. And while the thrill of getting something Ms Moss had a hand in creating (how much of a hand is debatable. She didn't sit up all night stitching it all by herself, that's for sure) the appeal of celebrity collaborations is waning. Even Kanye West, who worked with Louis Vuitton on a range of trainers, deems it passé, referring rather distastefully to the actress Lindsay Lohan's stint as a designer at Ungaro as the " the 9/11 for celebrities doing fashion".

Consumers are increasingly knowledgable about high fashion and more interested in buying clothes a prestigious designer has created at a high street price – such as the upcoming range by Lanvin for H&M – than something by a high-profile amateur.