The thirtysomething blues are as black and as sweet as Maya Angelou. They sing to you in the morning and keep you awake

at night. Theirs is the sound of a lone harmonica in the empty tube stations of your mind. It is a crisis of sorts, a spiritual rebellion, when you believe that opportunity is what you had in the past, and time itself is eating away at your future. When you realise that gravitas is a quality won when gravity has taken its toll.

It is received wisdom among my peers that this, the fourth decade, is a time of reflection and insecurity. We are all at the age where we have mortgages and retain some ambition, yet we're up for a shot of the swings or the roundabout in the local playpark, and moan when a toddler skips the queue. We are blank and stationary at the last point when we will ever remember what childhood is. We have come so far, and think we have achieved very little, and even if we had conquered the world, would insist that we have not earned our lines.

Those myriad of clues surrounding encroaching middle age, include not so much crow's feet as winged serpents settling on the eyes, those glittering sockets which more and more convey a little hurt and frequent disappointment. Not so much those stark white hairs around the temple, as a spooky fog around the citadel of a retreating ego. Maturing people often get smaller instead of bigger, more cowardly instead of brave, more pedantic than laissez-aller. When you get on a bit, life, it seems, is something left over from work, for which people buy you slippers, during the good times, and Viagra, during the bad.

Ageing is boring because it is effortless, it requires nothing of you but breath. Ageing is the greatest affront to man ever known. An added insult to what we know is something of a con. The Greeks compared mortality with an arrow in flight, swooping down on its prey. We are all walking dartboards. And on this mundane journey toward wine-collecting and the afternoon nap, you begin to laugh in your sleep, as I always have. You start to receive boxes of notelets as gifts from well-meaning and grateful ''friends'', and succeed in building-up a fantastic collection of writing paper featuring flowers and woodland fauna.

You give up drink because you are scared that three days a week under the wheels of the wagon mean you might be turning into an alcoholic. One drinks Hooch, bevvy so uncool the under-18s won't touch it. And we don't have hangovers anymore, we take a coma.

Sisters and collegues refer to nighties, when all you've ever worn in bed is a smile. You think the Bar-B-Q is a fun alternative to eating out. You show people photos of foreign holidays with the apology, ''Of course, I was thinner then''. This is a symptom of inner fatigue, the beginning of the decline into fully-blown passivity.

You would prefer more madness than method in your less than passionate existence, but the latter is safer. You start matching your partner's socks, or, at least, you think you should, because other couples are keen on exhibiting any domestic effort which symbolises caring and sharing. You are having a love affair with Marks & Spencer and the non-impulse buy, thanks to their refund and exchange policy. You would try to improve your sex life but you can't be bothered. You try to write a column that doesn't mention sex and fail at the sixth paragraph. You're not sure about having a kid, but you think you want a cat.

Your mum gives you a purse-size anthology of daily meditations, because you complain of feelings of superficiality. So profound is their insight into your desolation, you realise you would be happier having plastic surgery, and bagging a date with the bite-size Antonio Banderas or Jean Claude Van Damme. You wonder why your bum and thighs have a condition known as cellulite, as it only appears when you are heavy. You buy Greatest Hits albums because you don't want to risk 15 quid on a song you don't remember. You finally find an interest in politics.

You think you should take up a hobby because you truly feel that part of you is not being stretched. You think you might be a natural performer and wonder if it's too late to try the stage. You start writing stand-up comedy material instead. Your partner keeps coming home with invitations to various ''functions'', and although you detest the word, you cannot help but feel that you are comparable with any organ which fulfils its obligations.

Can't wait. Roll on 31, I say. When you begin to insist on having fancy dress parties because people are failing to impress you by being themselves. When you buy Bridget Jones's Diary and think it's funny.

All this and more I must look forward to, the pushing of 40, and more importantly, the fending off of 50. And for now, and others like me, it is enough that I feel 30 instead of something.