It is a year today since I last washed my hair. My days of rubbing chemical-laden detergent into my scalp are over. My hair now enjoys a product-free life.

First let’s get a few things straight. My hair is not in the least greasy. In fact it’s quite soft. And neither is it, in any sense, ‘dirty.’ I rinse it with the shower spray every two or three days to get off the dust and sweat. Then I comb it through, push it into shape and leave it to dry naturally. Total time outlay: about two minutes. I also brush it rigorously for thirty seconds or so at least once a day with a bristle hairbrush which I’m careful to keep very clean. Sluttish I am definitely not.

I’m assured both by my hairdresser – who now cuts it dry for me about once in six weeks – and by sensitive-nosed family members that my hair smells fresh and clean. ‘Bit like a cat’s fur when it’s just had a good wash’ says my daughter-in-law.

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Several people have noticed that my hair looks different and commented approvingly. The truth is that my hair has always been fine and ‘flyaway,’ especially when just washed – difficult to manage other than very long or very short. It now has more ‘body’ stays where I want it to and looks better than it’s ever done.

I’m also around £120 better off than I was a year ago. My regular dry cut is £10 cheaper than my former ‘cut, wash and blow’ and I’ve saved the cost of several bottles of shampoo.

So why do we do it? Well I reckon we’ve been well and truly conned by the shampoo manufacturers. Somehow, starting from early in the 20 century, they’ve convinced us – gullible mugs that we are – that it’s essential continually to wash away the sebum, the natural oil which moisturises your hair, with harsh, often quite expensive, detergents.

And then, because that can leaves the scalp flaky and hair dry and lifeless, those same con-men gleefully sell us conditioner, gel, wax, spray and a whole raft of other expensive products to make our hair ‘manageable’. Very soon after we have to detergent away the products and we’re trapped in an absurd and costly vicious circle.

No wonder the UK ‘hair care’ market is worth an exploitative one billion. If six bottles of shampoo a year are bought by, or for, every one of Britain’s 60 million inhabitants at, say, £2 a throw I make that £720 million annually spent on shampoo alone – and that’s probably a conservative estimate.

Are people really seduced by the pseudo-science in the ads? Dove, for example, tells us that its ‘nourishing shampoo’ comes with ‘weightless nutri-oil technology’ - whatever that means. Then there’s hype which reads like the worst sort of fourth rate poetry such as Herbal Essences’s ‘shimmery pearl and rose extracts will add flare to your hair.’ And what about all those meaningless and pointless statistics when they tell us for example, that 86% or 500 users said their hair was better or the same after using the product?

Most of the adverts are all desperately misleading anyway. Advertising Standards Authority notwithstanding, we’re in snake-oil territory with shampoo. A survey conducted by The Sun in 2010 found that almost a quarter – and I’m surprised it isn’t more – of women featured in shampoo ads are wearing artificial hair. In my book, that is perpetuating untruth, aka lying.

"In my book, that is perpetuating untruth, aka lying."

It’s hard to get a medical point of view on hair washing. Doctors know that it isn’t important – but it isn’t medically harmful – so they tend not to comment. There is however a newish breed of self styled experts known as ‘trichologists.’ The most famous of these is Philip Kingsley. He works in London and Manhattan and is widely quoted in newspapers on both sides of the Atlantic whenever hair health is discussed.

Asked recently by New York Times about people like me (and The Times journalist Matthew Parris) who’ve given up hair washing, he said sourly: “These people have just gotten used to their hair being greasy and dirty. They just don’t notice it anymore” Well that, Mr Kingsley, is absolute and utter twaddle. My hair is neither greasy nor dirty.

But of course you can’t rely on Mr Kingsley for a disinterested scientific opinion. The quite expensive range of Philip Kingsley hair products are sold internationally. Of course he wants you to buy lots of shampoo. I would too in his position.

So give it a go, why don’t you. Let’s see if we can dent that £1 billion. My only warning is that you have to be slightly strong minded for the first week or two.

If you’ve detergented your scalp all your life, several times a week, it will be used to having to produce extra sebum to compensate. When you stop shampooing it takes the scalp a short time to adjust. In other words you might have to put up with the dreaded grease for a very short time. I found brushing helped with that and, trust me, it was absolutely fine after about 10 days.