Zebru Responsive Long-Sleeve Top, Salewa, £80, salewa.com

This mostly merino base layer is the lightest garment we tested. Despite its light feel, the Zebru packs a punch. Built to a figurehugging design, it’s made with synthetic yarns containing minerals that, apparently, have the ability to absorb far-infrared radiation from your body and slowly release it back, delivering longer-lasting warmth. Frankly, it’s tricky to determine whether this stacks up, but we can attest that, for its weight and thickness, the Zebru performs well when you’re hillwalking in winter. It lacks a few flourishes, but does have a low hem, which prevents the top shuffling up your back when you’re wearing a pack. VERDICT 8/10