The world is full of private practices. We may find some unnecessary, harmful or otherwise disagreeable; and others objectionable on moral, aesthetic or religious grounds. None the less, when these are done in private, we are reasonably tolerant.

Apart from such private vices, there are also private virtues - ascetic practices such as abstinence, fasting and the like. These are entirely admirable and are directed, as is martyrdom, towards a higher end. Few saints got high marks for doing the odd things they did by doing them in public. Conspicuous prostration on a cold stone floor throughout the night was rather frowned upon by my novice master; he called it the sin of pride.

I think rather the same way, to bring this into the world of food, about the recent grand assembly of the International Vegetarian Union in The Hague. As a way of life, vegetarianism is a fine thing if you fancy it; it does little public harm (though obviously livestock producers disagree and, were it to become universal, our world economy would suffer); and it suits some people. If one admits religious gurus with all sorts of weird propensities, there is no reason to find food gurus absurd. Obsessives and monomaniacs abound, and each seeks to convert others to his way of thinking.

It is the public parading of private concerns that brings out the barmy, and The Hague was no different in kind from Rio eco-freakism and the forthcoming Cairo ding-dong about population. Such events do us a service in revealing how extraordinary are some of the things humans seem to like to debate. I am not one of those people who are going to go to war over whether egg-eaters are violating the purity of the vegetarian creed; it is unlikely that I will weep over the fate of cooked vegetables.

Such gatherings are forums for contentiousness and Anglo-Saxons are world leaders in fruitcake arguments. Only in India, where vegetarianism (practised by 35 per cent of the population) is for some a matter of religious observance, is there a higher percentage of vegetarians than in the UK (10 per cent, according to some). France (1 per cent) comes at the bottom of the league, though I am fairly sure that not all countries are included in the tally, for I have never yet seen a Spaniard or an Argentine willingly ingest anything green. But extremist sects (by which I mean any that carry a good idea too far) exist for the sake of argument, and The Hague was no different in this regard. When a chef prepared a garlic mousse with fried aubergine and a flan of courgettes and canary grass for the assembled faithful, there were howls because creme fraiche and egg-whites had been used in its preparation.

The fathers of any church have a hard time of it. But it is precisely this religious aspect of vegetarianism that I find most suspect, for religions (which are supposedly a matter of private conscience) are also coercive, and nothing is today as ethically 'pure' as vegetarianism. (As a recent letter to this paper sagely stated, if everything we eat suffers by being eaten, what are we meant to eat?)

Following closely on these 'ethical' principles, vegetarianism is buttressed, as one might expect, by political arguments: 'meat widens the gap between the rich and the poor; rich countries destroy acres of forest to produce grains with which to feed their cattle; it takes 16kg of grain to produce 1kg of beef' (though, of course, if we did not eat this livestock, nothing leads us to suppose that cattle would not continue to eat, nor that their numbers would not increase and therefore consume still more). There are also the 'scientific' arguments, which range from: meat stays a long time in the digestive system and is therefore 'corrupting, and causes many illnesses' (but so does protein deficiency); to the assigning of all chic modern ailments, from cardio- vascular illnesses to cancer, to our eating of meat and dairy products (though, again, this ought rightly to be compared to dying of famine and all those diseases now obsolete thanks to a more balanced diet.)

As for the supposed better health of vegetarians, let us say they also tend to be highly health-conscious in other respects: exercise, abstemiousness and so on. But life and how one leads it seem to me a matter of choice and personal conviction, and this new vague theism of the Vegetarian Church (you know it is a church because it is full of don'ts and short on dos) with all its Rousseau-istic aspects of the primacy of something called 'nature' strikes me as yet another forlorn pursuit of a fictitious immortality. Seek that immortality as you will, but kindly do not proselytise.