Many people solve winter with chunky overcoats.

This works if your idea of a great day out is standing at bus-stops. But kids love a good run-around any time of year. And the younger they are, the more time they spend on the ground – inspecting leaves and bugs, comparing puddles, crawling through shrubs.

The only way to guarantee mobility and warmth is a good base layer. Not just for sports, but for normal outdoors play. This is the single smartest thing to stock up on in the autumn, but amazingly still not a mainstream purchase amongst UK parents. In Scandinavia, kids literally sleep in them. They’re just bought in bulk for everyday use.

Base layers provide unparalleled comfort – thin and comfortable yet insulating – but these are pricey materials and used to be the preserve of skiers. Luckily base layers are gaining some traction with young footballers and rugby players for the coldest training sessions. Kids see seniors in “man-tights” so each season you see more young players turning up at training wearing good old-fashioned long johns – available in anything from merino wool to polypropylene mixes.

If your kid is comfortable wearing merino wool, then these feel superior the minute you pull them on. I have two kids who scramble through their drawers to dig out wool layers on a cool winter morning, as they provide instant cosiness. My third child finds even merino wool irritating next to the skin. If you rule out wool, then there are many man-made fibres which will last longer, fit more snugly and are half the price or less. Team Magnus' own Tundra wolf brand are made in Italy in a patented XDry material.

And style? Short-sleeved tops will do the job for messing around and for tennis and other sports where the kids don’t stop often.

If it’s a stop-start activity – like some team sports – or with altitude changes – like skiing and hiking – then there’s no way around the collared, long-sleeve top, and the more expensive two-layer construction is essential. You’ll find ideal man-made fibre inner, wool outer combos.

Finally, there are roll-necks and hoods which add flexibility in changeable weather or if you’re cycling – but these are hard to source for kids. Consider searching for XS women’s options.

The brands I look for are from Scandinavia or New Zealand, as they always offer higher wool content and their home markets know their stuff. Price tags for base layers can come in ahead of some cheap puffa jackets, which might seem counter-intuitive. Layering is essential for comfort and range of movement, which is what makes even expensive materials great value.