In September, when British designer Mark Fast first sent a few plus models down his Spring/Summer 2010 collection runway, the aftershocks were felt all around the world. At the time, we declared: “Curvy models are having a moment.” And nearly six months later, that moment is still going strong.

Plus model Crystal Renn walks the runway for Mark Fast's Fall 2010 Ready-to-Wear Collection at London Fashion Week. (Courtesy of Style.com)

It has no doubt been helped by Mr. Fast’s continued inclusion of size diversity in his Fall 2010 Ready-to-Wear show as well, which debuted at London Fashion Week on February 20.

The renewed commitment is commendable because members of his own design team quit last fall amid accusations that hiring models of more than one size was nothing more than a publicity stunt. But it seems that Mr. Fast is no flash in the pan after all.

We applaud him for sticking to his guns and not backtracking with a more mainstream set of models for his newest collection. His S/S 2010 show last September could easily have been merely a fluke, a gimmicky move that attracted headlines but effected no actual change in his design strategy.

But instead, he seems to have dug his heels in and set himself apart as a designer who is intrigued by the notion that even women who wear a size 12 want options for high-end clothes — and indeed have the power of the purse behind them.

However, before we get too far into this lovefest, we have to quibble with a few fit issues that became evident on the runway.

Among the models he hired for London Fashion Week was Crystal Renn, the most famous and well-paid of plus models working today. Hers is not a particularly difficult figure to fit, what with her small waist and well-proportioned bust and hips.

Yet in the above still frame from the show, even allowing for design elements like ruching, the dress is clearly pulling in myriad directions. Her breasts are straining the fabric, her hips look mashed inside, and the sleeves look downright uncomfortable. A well-tailored dress should not restrict movement to that degree.

Other creations from the collection would have had better success on her proportions, such as the gold-hued asymmetrical belted dress that appeared halfway through on a standard sample-sized model. The cut of that gown, with the defined waist and elegant draping, would have easily lent itself to an hourglass figure. (You can see the full collection in slideshow format here.)

With such options at his disposal, it’s odd that Mr. Fast and his stylists didn’t make more inspired choices for the plus models. There is no reason to stuff women into ill-fitting garments that seem to call attention to lumps and bumps rather than flatter the fuller figure. But perhaps if he put a too-flattering dress on a plus model, how would anyone know she was plus at all?

This isn’t to imply that what Mr. Fast has done is not groundbreaking and inspiring. It is so refreshing to see this level of body consciousness in such a mainstream setting as London Fashion Week. But his next challenge should be not only to design clothes that plus-size consumers can wear, but to make garments they will want to wear as well.

Of course, the question remains: When will petite models get their day on the runway? The shorties of the world want to be represented, too!