SOMETHING I bought a few weeks ago is turning out to be a life-changer.

My new coat could mean the end of winter as I have always known and endured it. 

The £135 polyester garment does something that no coat has done before. It actually keeps me warm. 

I am a challenge to any coat because I am cold-blooded as a worm. All my life I have tended to shiver when others are warm, and even when they’re hot. When my companions are shedding their jumpers, I am hunched with hands in pockets. The cause of my icy condition may be languid metabolism or it may be that I’m quite thin and don’t have enough fat for normal human insulation. 

What is this amazing coat I’ve bought? Basically it’s a duvet, but a duvet with two arms, several pockets and a zip from chin to shins. 

The fashion industry doesn’t market these mobile cocoons as “duvet coats”. They seem to call them “puffer coats”, “baffle coats” or “padded coats”. 

The shops are full of them and in the street you must have seen people wrapped up in them, particularly women. Now men, too, are taking to wrapping themselves in the wonder garment, with its duvet-style padding bulging in every dimension.  

On TV news I saw a top politician wearing a duvet coat as he headed for a meeting at the Cabinet Office. That encouraged me to buy one. “If it’s smart enough for a minister to wear in Whitehall, it’s smart enough for me to wear in Winchester,” I told myself.

I had been considering such a purchase for months, because I had pondered the similarity between (a) the stuffing in duvets and things like (b) loft insulation and (c) the wool on sheep. They are all light and fluffy and don’t let heat through. 

Despite my worm-like physiology, I didn’t get round to splashing out on a so-called winter coat till about three years ago. It was a formal wool tweed-looking thing with a posh velvet collar. It left me cold! Not light and fluffy enough to keep heat in. It was heavy and thin and let heat out, specially round my poor back, which froze.

I felt warm as toast the minute I tried on my duvet coat in the shop. I wore it home and all the way my body felt like it was still indoors. Duvet coats are brilliant. 

Mine is changing my life because now I can venture out and exercise in wind and ice. Without getting cold, I should enjoy better health, less prone to colds, flu and worse. The coat could even change where I live. I had been planning to spend winters abroad when I get older but now I’m more likely to stay in Hampshire. 

Duvet coats are increasingly widespread, so prices are likely to fall. I think they will have a beneficial effect on the world. They are a revolution, as yet unnoticed. 

For old people in cold climates around the globe, duvet coats will bring freedom of movement in winter. For the desperate poor, unable to afford adequate heating, duvet coats will at least provide a comfortable garment that will keep them warm at home. 

The effect of that is likely to be greater longevity and, in Britain, less pressure on the NHS. 

People of all ages will find themselves doing more outdoors in winter. Maybe outdoor events in winter will become bigger. Relieved of miserable winter cold, people should be happier. 

Even the planet stands to benefit, through fewer people turning up the heating when getting in frozen stiff after a chilling time outside. That means less carbon emission. 

If you doubt that a clothing fashion can be a revolution, look to the hands-free backpack, which has changed the world. Until the mid-1980s, indispensable backpacks were worn only by youths, soldiers and people on expeditions.