Not only are the Girlfriend Collective Compressive High-Waisted Leggings (£65) completely opaque (and very flattering), but they're sustainable, too. The brand utilises up to 25 plastic water bottles to construct each pair of Compressive Leggings, which come in two lengths — long and a 7/8 crop (shown here) — and a fun array of bold colours like periwinkle, red, and purple, the dyes of which are also eco-friendly.