The Matthew Williamson Dress, from the Spring Summer 2009 Catwalk show. Notice the shape of the bandeau and the jewels on the pockets. It sells for around £900.
Lipsy's Version, on Asos.com, sells for £65.
Boohoo.com's Jasmine Statement Jewel Cocktail Dress, sells for £25.
This just shows how influential catwalk designers really are. When it comes to them designing a wearable product, the result is copies. Lipsy would have to be the worst criminal, as their current collection is pretty much solely based on the Matthew Williamson dress.
I guess it's to be expected, and nice to have a choice.