Thermo-regulating and naturally odour, stain and wrinkle resistant, it has been a circular fibre long before the expression existed. And while its production can be environmentally and ethically problematic if badly managed, the best wool producers are sequestering carbon and creating authentically regenerative natural ecosystems. But the thing we love the most about wool is that it scores highly on the most important metric – its in-use footprint. Long-lasting and requiring minimal cleaning, wool-based garments are truly sustainable, a point that a new breed of brands are making strongly.