Join Vonny Lang this week for a 7 Day Challenge that puts eco-conscious lingerie brands in the spotlight. Finding sustainable pieces without spending a fortune can be tricky, so Vonny’s task is to source seven items for under £100 in total. For her penultimate item this week, she's reviewing some Cotton:On ultra soft booty lift leggings. Did she keep within budget, and which one does she love most? All will be revealed on Sunday.

"When I was buying these I think they were actually on sale but this looks like a really good piece and the print is quite versatile." Vonny Lang