The Mountain Equipment Compressor Hooded jacket is the workhorse of your kit. It’s the ‘throw-it-in-your-pack’ jacket. It’s your ‘put-on-over-a-shell’ jacket. It’s for those windy summit stops, for when the cold just gets too bitter on the return. It’s the standing around jacket.

The great advantage of this super-lightweight belay jacket, is the synthetic material, in this case PrimaLoft ONE – the top end synthetic material. Using a synthetic insulating material, as opposed to down, means it retains its insulating properties even when wet. This means you can pop it on over your waterproof when things are looking bleak. I wore this jacket on a particularly windy, wet, and all-round grim weekend in Snowdonia, over my shell when we stopped, or were high, and the very last thing you want to do in 50mph winds is take anything off. I just popped this over the top and was fine. The next day was dry but very cold so I just wore this, my waterproof happily languishing in my bag.

The Compressor is the lightest of Mountain Equipment’s synthetic insulation range. It uses 60g insulation in the hood and body, and 40g underarm and in the side panels where more moisture builds up (it’s also very quick drying). John Manning reviewed the heavier Fitzroy (710g size XL) in the December 2013 issue of The Great Outdoors and it won the Best Buy.

The hood is insulated and there’s drawcords around the face that pull from inside the jacket and it fastens well enough, but I’d have liked a loop to pull on the outside of the jacket too. The chunky two-way zip fastens just at the chin, and the neck is wide and comfortable. There are two hem cord pulls. The handwarmer pockets are covered by a hip belt, but there’s a big chest pocket on the left-hand side that can just about take a map. The cuffs are elasticated.

The outer material is the lightweight Helium 30 that also holds off a fair amount of wind, but not rain although there is a DWR treatment. I had been a bit worried about it, as it seems so light but I’ve worn this a lot without much wear.

This is a simple, but well designed jacket, but one that I reach for when the skies are grey. There is room for a synthetic belay-style jacket in everyone’s kit box – it’s just so versatile. And, of the ones I’ve tried, this is the one I’d buy. A woman’s version is available for £120, and the Compressor Vest costs £90.