Brian Viner: If you see me in leather trousers, please don't scoff

Forty years ago today, a new satirical magazine was born. And so, oddly enough, was I. Accordingly, I have taken extremely personally all those articles about Private Eye's 40th birthday – how it has retained much of its youthful insouciance despite looking a bit monochrome and dog-eared, how it has perhaps got weightier in recent years. Take away the "perhaps" and that's a pretty accurate description of me, too.

On the whole, though, I feel rather sanguine about turning 40. If you're moderately satisfied with your life's achievements so far – and without wanting to appear smug I am blessed with a happy marriage, three healthy kids, a job I enjoy and a no call-out bonus from the RAC – then what's the point of getting depressed about landmark birthdays?

I know, for example, that Frank Skinner was delighted to turn 40, yet felt almost suicidally gloomy about turning 30, when he was an unemployed alcoholic seemingly going nowhere, drinking a bottle of sherry every morning before he could even get out of bed.

On the other hand, a column of bold ticks on a notional mid-life checklist is no safeguard against the sudden urge to wear a diamond ear-stud or leather trousers or buy a second-hand Porsche or attend an Eminem gig or walk the Pennine Way on your own, those classic manifestations of mid-life crisis. Happily, I don't have those urges, still less an urge to run off with our 18-year-old babysitter – even though, with those four-inch platforms she wears, I'd stand a middling chance of keeping up with her.

A fortysomething neighbour of ours has succumbed to at least one of the above, however, with no apparent sense of how daft he looks. But if it makes him feel better, who am I to scoff? We're all in this ageing lark together, so, unless they involve the babysitter, we should be tolerant of the ways in which folk deal with it. For repeatedly flashing her thighs at premières, 40-year-old Carol Vorderman found herself on the receiving end of a most cruel arrangement of consonants and vowels. But I was cheering her on, full of admiration.

Besides, somebody wise told me the other day that 40 is worth celebrating, as an age of experience without decrepitude. I take comfort from that, and from the knowledge that I share my birthday with two creative geniuses, the younger Johann Strauss and Pablo Picasso, whose greatest legacies, respectively "The Blue Danube" and Guernica, were not completed until after they were 40. I am also comforted by all those market-research questionnaires that categorise 35-44 as an age bracket. Obviously that makes 45, not 40, the official onset of middle-age.

Now, you might discern a slight note of desperation here, and it's true that for all my outward cheerfulness, turning 40 has caused me some introspection, not to mention more than a few sessions on the bathroom scales and in front of the mirror. But then, if you consider the historical importance of today's date, it's hardly surprising that I swing both ways.

Like many Scorpios I have no time for astrology, but I do think one can extract a certain significance from historical events on the date of one's birth. And 25 October marks the anniversary of one of this country's greatest military triumphs, yet also one of its most resounding military disasters – the Battle of Agincourt in 1415 and the Charge of the Light Brigade in 1854.

Clearly, that's why I'm mildly schizophrenic about my 40th birthday; because 25 October is a date on which the pendulum traditionally hits both extremes. One further example: I don't suppose the founders of the wickedly entertaining Private Eye ever realised that the date of their inaugural issue was also the 122nd anniversary of the publication, on 25 October 1839, of Britain's first railway timetable.

b.viner@independent.co.uk