I was sitting at a table with my family. Absent-mindedly, out of the corner of my eye, I noticed a leaf, and idly tried to pick it up. But it would not come. My children starting laughing at me. They pointed out that it was actually a picture of a leaf printed in a newspaper. I was having a senior moment – one of many that I experience on an increasingly regular basis.

The dropping off of brains cells is only part of it. The journey of all parents is ultimately the same – from the revered to the ridiculous. This is a natural process that will happen in any case and is healthy for the individuation of the child. Playing noughts and crosses in the wrinkles on my forehead, as they have done, is doubtless part of that healthy process.

But the speed of change in society means that now it goes well beyond the simple fact of “being old”. Adults almost inevitably will become idiots because most of them cannot keep up – primarily, but not only, with technology and changing attitudes.

There was a different kind of idiocy gap when I was a teenager – a cultural gap. Pop and rock music was quite alien to my parents, most particularly punk, a phenomenon they found utterly bewildering. My parents’ preference for Frank Chacksfield and Mantovani put them firmly in the neanderthal camp, along with their terrible taste in clothes. By the time I was 15 they were absurd to me, beyond the pale.

I never dreamed that the same would happen to me – but for different reasons. The presence of balding pates and withered shanks at rock concerts, or the continuing interest of the middle aged for style and fashion, means that the cultural gap I experienced is now less obvious.

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