£130 189g (M)

Fabric: 50% wool, 25% polyester, 22% polypropylene, 3% elastane Sizes: XS-XL

Men’s version: yes hellyhansen.com

I have never found a better base layer fibre than polypropylene; and Helly Hansen’s Lifa, in various guises, is the clear leader in the polypro stakes (and, had a plain Lifa Crew been submitted for testing, it would have won Best Buy, especially at £35). In recent years the brand has experimented, mixing fibres, creating dual layer tops, but never, in my opinion, achieving the same degree of super-fast moisture removal and evaporation.

This top, which blends wool with polyester, polypropylene and elastane, falls into that bracket: because of the wool element it can never be as fast-drying as pure polypro, but it does have other qualities that elevate it, especially for cold weather use. For a start, it has ‘thermal mapping technology’; different densities of material depending on where your body needs warmth (I counted five in a variety of patterns). It has laser-cut holes under the arms, under the bust and in a wide panel down the spine to deal with heat from a rucksack. Seams are minimal and tiny, and the stretch fabric is incredibly comfortable to wear. The collar is almost chin-height, with a guard against the short zip. The length is generous which helps anchor the top; stretchy numbers like this tend to roll up toward the waist. Crucially, though, the fibres are blended (knitted together) rather than layered, so despite a 50% merino content, my skin never reacted to it as it would a pure merino top. It holds more moisture than polypro but less than pure merino and has the odour control of wool.

As a winter layer it’s a cracker, especially if, like me, you get itchy with pure merino next to the skin. Yes, the price is eyewatering, but construction is complex and the fabric is technical.