My mother thinks I'm finally losing all sense of values. Or maybe just plain value. I have just put my hand in my pocket and of my own free will forked out £45 for a pair of runners.

Now nobody stood behind me with a dangerous weapon, I was not on day release from the local psychiatric hospital and, unfortunately, I am not on the list of past National Lottery winners.

The recipient of these wonder-shoes was my 10year-old son. He primped and paraded for 15 minutes in the sports shop before announcing them acceptable. They'd want to be at that price!

The fact that these trainers are probably made side-by-side in an Asian sweat-shop with the cheaper brands held no sway with this discerning pre-teen. Sporty Spice wouldn't be seen dead in a pair of the chain store variety, so why would my darling son?

Street Cred is the key here.

The offending articles would not be to my own personal taste, but I suppose that is to be expected. It would rather defeat the purpose if your 40-year-old mother was seen sporting a pair of luminous orange, padded trainers that look like you should need a provisional licence to manoeuvre in them.

They come with a descriptive blurb that would lead you to think it was a space ship they were talking about rather than a pair of shoes - they appear to be built rather than simply made.

And the funniest part of it all is that even with all this aerodynamism, support and shock-absorption that would be truly worthy of the creme de la creme of the world's athletes, the most they will probably be used for by my plump offspring is a 10minute dash to the shops to get the latest soccer magazine.

Sad, really!

So, you wonder, what is she blathering on about? She still went out and bought the things, didn't she? Is she just another closet designer snob?

Well, it all boils down to long division in my books.

Before you decide I really am a candidate for the funny farm, let me expound on my theory: you take any item of clothing and divide the price of it by the number of times it's worn (bear with me) and you get a real idea of what it's costing you.

So, my theory is that while a dearer pair of runners are harder to justify on the day of purchase, the one enduring truth is that I can guarantee they'll be worn day in day out, everywhere, until they are eventually deemed a health hazard by the other members of the family.

And in the end that kind of value, as they say, beats them all.