One of my readers - London Rose - wrote to say how invaluable she'd found the angora 'chauffe-reins' back warmer from Lidl that I featured back in November.

With the snow firing itself horizontally at this house today, then, and spring feeling very far away, I thought I'd mention a few more I've found, since winter clearly isn't over yet. 

Damart sells a range of supports that double as back warmers. I can't vouch for them, as I haven't tried them, but I do know that their other products are good, so they might be worth a punt. They are much more expensive than the Lidl product, but possibly less bulky to wear, and don't contain angora. 

They are all listed as Supports, under Warmth Accessories in the Thermals section. The jacquard one at top left is £32, lined in Damart's own-brand Thermolactyl and has a velcro fastener. It comes in a range of sizes so you can get a close fit, and the jacquard design looks like it wouldn't seem too naff if someone accidentally glimpsed it when you raised your arms.

The black 'walking belt' is £40 and is specifically designed to keep your back warm when you're out and about, gardening, rambling, etc. It's made from a Thermolactyl wicking fabric and fastens with Velcro, making it very adjustable, but it's a true support, with four rigid bones in it. Useful if you suffer from an aching back as well as a cold one.

The unisex pull-on belt is the cheapest at only £19 and is again made from Thermolactyl. It comes in two depths and three colours - skin, navy or white. The navy probably looks the least medical of the three.

All the supports have lycra in for a snug fit, and look as if they would hold you in a bit, which might be no bad thing after too much Christmas pudding. 

It's cold today. Outside it's about minus 8, taking windchill into account, and in this office it's about 17 degrees.

Seventeen degrees isn't illegal, so even if I worked for somebody else, which I don't, I couldn't go on strike - the lowest limit for a legal office temperature is 16 degrees. But the optimal temperature for working is 21 degrees, so we're falling far short. Even sitting next to my plug-in radiator, however, I'm not going to get my working environment much warmer, because this house is a draughty old pile, so I have to dress warmly to compensate.

As I write, I'm wearing multiple thin layers. To stay warm in winter (or, increasingly, in an air-conditioned office), you need to trap as many separate pockets of air against your body as you can, so several thin layers are better than one big one. This is why fine wools work better than thick ones, because the finer the fibre, the more air it traps.

There are also key areas to keep warm: your hands, your feet, your head and the small of your back. Also, if you're typing, it helps to heat your wrists and the backs of your hands. I wear fingerless gloves with a long gauntlet section which means there are four layers covering my wrists, very effectively heating the blood supply to the fingers. I also find it's useful to keep your neck warm, so I either wear a poloneck in winter, or a scarf to fill in the gap of a v- or crewneck.

And under it all go my thermals - which go on in October and don't come off again until spring.

It was my friend Janice who turned me on to thermals. I had an image of them as hideous waffle-knit white things that your gran wore. But Janice, back in 1983, cycled to work every day, even in the dead of winter, and was a huge devotee of Damart. Her Damart bodies and camisoles came in all colours, with lace trimmings, and were pretty enough to be seen as tops. I was duly impressed.

I bought my first set of thermals from Patra when I was doing outdoor photography in Cornwall, and they proved invaluable when I was lying in puddles taking pictures of yellow brain fungus. But since moving to the countryside, I have become an absolute devotee of thermal undies for everyday wear in winter. They are a godsend because they enable you to wear roughly normal clothes rather than bulking up like the Michelin man every day - and they also go under businesswear perfectly easily if you have a chilly office or a long, cold commute to get there. For this, long-johns are a much better option than tights - who could resist this pink leopard pair from Winter Silks? (this company also stocks thermals in knee-length for under business skirts if you have a daft office code that requires tights).

I wouldn't bother looking in the shops for the good stuff - it's nearly always white or cream and looks as frumpy as it ever did. The best items are available from specialists online, such as Winter Silks, Damart or Patra. You can also get thermals direct from China, via Ebay - most silk thermals are made in China anyway, so by doing this you're cutting out the middle man.

Thermal fashion has moved on apace and not only is there a wide variety of colour and design to be had, there's also a wide variety of insulation. Damart, for instance, offer their Thermolactyl thermals in five different weights, and Winter Silks offer theirs in three. The latter also have long johns with a low waist, to go under your low-waist jeans or trousers. In some ranges, you can buy strappy camisoles, sleeveless vests, short-sleeved or long-sleeved vests, tops that look like everyday wear, briefs, long-line briefs, French knickers and longjohns.

For strenuous activity, your thermals should be thin, but for sitting around the house they should be thicker. I know this seems counter-intuitive, but thicker ones make you sweat if you undertake strenuous activity. All thermals should be relatively tight-fitting without being restrictive - like a second skin, and should have cuffs to cut out draughts, like these cotton waffle/silk ones from Winter Silks. For myself, I go for the full Monty - long johns and a long-sleeved top, but if you need just a little insulation, a short-sleeved top, sleeveless vest or camisole is still worthwhile.

Over the years I've tried thermals of just about every material, including synthetics, cotton, merino wool and silk. One thing I've learned is that whatever the fabric, it does pay to buy ones that are as pretty as possible - a bit of lace at the neckline does wonders for morale, like this blue top from Patra. Nude and white are useful, but it's also nice to have a bit of colour - I have sets in lilac, orange, black and pale grey.

Fabrics

As to material, my personal favourite is silk, which doesn't itch, doesn't make you sweat, is slippy under your other clothes and which you can even sleep in. My silk thermals come in whisper weight, lightweight and heavyweight ribbed mulberry silk, each offering a different degree of insulation. In really cold weather, I put on two pairs.

Cotton thermals are fine for low-activity wear, but no use if you're doing anything that builds up a sweat, as when they get damp they stay that way. But for round the house, they work very well. I have a thick cotton waffle set from Lawrence Corner that is Forces issue - very warm indeed, with long cuffs.

Modern wool thermals aren't at all itchy, in case that idea puts you off. They're usually made from merino, which is very thin, smooth and silky against the skin, and are often blended with silk. Wool thermals also have a lot of stretch, which makes them very comfortable to wear. Winter Silks even make a blend of silk and cashmere, if your pocket will stretch to it, which comes in a taupe colour or a dark grey.

Personally I'm not so keen on synthetic thermals, which don't seem to me to have the insulating properties I'm looking for, though I did recently find a set with a back-warming polarfleece section, which is very useful. However, I've never tried the really modern or high-end synthetics, so I may be being unfair. A friend of mine wears synthetic cycling thermals for his work as a gardener and absolutely swears by them, and they have the added utility of drying in minutes, so he can rinse them out each night. This girly raspberry silk cami and French knickers from Damart are in the firm's Thermolactyl brand but with a satin finish.

What synthetics are absolutely invaluable for, however, is for fleece layers and outdoor clothing, especially in wicking fabrics such as those made by Polartec, which wick moisture away from your skin. And if you're eco-conscious, synthetic is the way to go - Polartec is made from recycled pop bottles, and if you send back your Polartec clothing to a company like Patagonia when you're done with it, they'll even recycle it for you.

Damart: www.damart.com

Winter Silks: www.wintersilks.com

Patra: www.patra.com

Polartec: www.polartec.com