WELL now, here's a surprise! In the areas of the country where there has been the most intense advertising of "safe sex", schoolgirl pregnancies have shown the biggest increase. These are also the same areas showing the most abortions and the highest incidence of venereal disease.

It was to be expected of course. After all, we know that advertising works and we know how it works. The advertiser doesn't have to say anything about the quality of his product. He doesn't even have to describe it in any great detail. But the one thing he must do at all costs is to keep the name of his product in front of as many potential consumers as possible. So, it doesn't matter what is said about sex: by talking endlessly about the subject you ensure it is forever to the forefront of people's minds. This is an incentive, a reminder if you like, that sex is one of the consumables which you might think about having - like a new fridge.

Sex used to have something to do with morality. All the great religions of the world cherished their codes of behaviour which told us what is right in sexual relationships and what is wrong. The reason why religion talks so much about sex is because it sees sexual relationships as basic to the life of the community. "Thou shalt not covet thy neighbour's wife" is a very sensible, practical rule: if you go around to covet Mrs Smith next door, you're going to get in big trouble with Mr Smith. The old religions were wise enough to notice that where sexual relationships are unruly the whole community suffers. Sex is perhaps the strongest impulse known to humankind and therefore it is bound to entail serious social consequences.

Nowadays, unfortunately for our personal and communal happiness, the helpful commandment "Thou shalt not commit adultery" and the prohibition on "fornication" have been replaced by a single instruction which is repeated by government spokespersons and social workers like a savage chant: "Wear a condom". You might be forgiven for thinking that the whole of western sexual morality has been reduced to that crude slogan - as if the mysterious and beautiful love between a man and a woman can be regarded merely as what the rutting pig knows.

Of course, even the diabolical officials who invented "Wear a condom" are obliged to realise that, however shrill their piping of this slogan might be, some people will have sex without a condom. What then? It doesn't matter, for you can have abortion on demand. Needless to say, many people do ignore the commandment to wear a condom and the result is that there are about 180,000 legal abortions in this country every year. Never has there been so much sex education and never have there been so many unwanted foetuses and deserted children.

What this says about our society is that we have lost the plot. We have so trivialised sexual relationships that people think no more about leaping into bed with anybody than they might think about eating an apple. So, by condoning early sexual activity, we are teaching our youngsters to destroy their adolescence. By accepting adultery and fornication we are encouraging the breakdown of social relationships. By using abortion as a means of birth control we are murdering our own kind in increasingly large numbers. And still all the talk is of progress. Nausea is the only response. And the reform of sexual morality.

* Peter Mullen is Rector of St Michael's, Cornhill, in the City of London, and Chaplain to the Stock Exchange.