Recycled Materials ‘Not Good Enough’ Says Startup Whose Synthetic Tights ‘Fully Biodegrade In Landfill’ Billi London, the startup founded by Sophie Billi-Hardwick and Marie Bouhier two years ago, set about creating a sustainable tights product. They say they now “own 100% of the biodegradable tights market” as hosiery industry behemoths lag behind.