The US arm of PETA has become a shareholder in Boohoo to persuade the retailer to ban the sale of garments containing wool.
It comes after Boohoo, which also owns PrettyLittleThing and Nasty Gal, announced plans to enforce a wool ban last month, but within hours it backtracked on the decision.
The original promise saw Boohoo pledge to no longer use wool across all its brands by autumn this year.