“BE AS pure on the out as you are on the in”, claims the fruit smoothie. Drink the cleanest water. Do something new. Flush out your system. Revive yourself. Start again. Purity.

Is it really something that you can buy? Picture the girl, glowing with health, in that EVIAN ad. OK, so it’s a bit obscured on the back of that filthy double decker bus; but we all know what they are getting at....

Somewhere, outside of this world of daily toil and grime, of litter on the streets and grit in your eye, there is a world of tranquility, harmony and health. Eternal sunshine. Unspotted, unsoiled, unspoilt. Clean. How the world was meant to be. People will pay anything for that experience; just ask Carol Vorderman.

You think doing a detox sounds a bit extreme? Well, how about chaining yourself up underground? Living in a tree for six months? Eco warriors they call them; their vision is of a world where man does not fill the soil, air and water with toxins and nonbiodegradable litter; where animals are respected and the earth and its resources are used in a sustainable way.

Some of them have even died in pursuit of their cause: a pure earth.

Why is it that we find ourselves with this deep longing for purity? Is it a spiritual thing? A sense from deep within? And how do morals fit in?

There’s more to purity than how you appear. We feel it to be important that our leaders are men and women of integrity, even though they so often demonstrate that they have their feet deeply rooted in the same clay that we are all made of. We want to be able to look up to the likes of David Beckham. Why are we disappointed when we find out what our heroes have really been up to? All of us know we’ve had dirty secrets. Is anyone, can anyone, be really clean?

Perhaps purity is just a concept, a useful sales tool for the marketing men. A utopian dream, a bit like one of those “whiter than white” adverts for Ariel automatic; an ideal of perfection that exists in our imagination only, along with other fairytale ideas like beauty, truth, heaven and love.

And yet...and yet.....something in all of us wants a cleansing experience that is deeper than a foam bath or the latest, zingy shower gel.

What does it really mean........to be pure?

See also: Purity in marriage Purity means Freedom Living in Purity