Mr Neil Parish, as well as being the Conservative MP for Honiton, is chairman of something called "The All-Party Parliamentary Group for Beef and Lamb".

Last month, in one or other (or possibly both) of these capacities, he commented on the results of an investigation that compared the retention of red blood cells in meat derived from food animals that had been mechanically stunned prior to slaughter with those of animals that had been shechita-slaughtered - meaning they had been stunned and slaughtered in one operation.

This investigation had apparently been carried out by academic psychiatrist Colin Brewer and consultant pathologist Peter Osin, both of whom were curiously described by The Times (23 September) as coming "from Jewish families," though (as The Times also revealed) their research paper had not been peer-reviewed.

Be that as it may, Osin and Brewer, commenting on the results of their investigations, announced there was no difference in the retention of red blood cells in either sample and, on that basis, they concluded, "if ritual slaughter… fails in its stated purpose of removing as much blood as possible, compared with other methods, then it becomes more difficult to justify and defend." The Conservative MP for Honiton could hardly contain himself. "If it can be scientifically established that [mechanical] stunning does not adversely affect blood loss then we can assure consumers of religiously slaughtered meat that stunning is compatible with their faith."

Except, of course, that the "stated purpose" of shechita is most certainly not to remove "as much blood as possible," and that even if a mechanical stunner were devised that somehow permitted or facilitated the draining of every last drop of blood from a carcass, its impermissibility to consumers of kosher meat would remain completely undimmed. In order to enlighten Messrs Parish, Brewer and Osin (and any who might be tempted to walk in their footsteps) I am going to explain why. But in order to do that I need also to say something of a more general nature about the laws of kashrut.

Telling me what is compatible with my faith is sinister

Here I can claim some expertise, because it is a subject that invariably comes up whenever I address non-Jewish audiences on "being Jewish". "What's wrong (I was recently asked) with a prominent Jewish politician eating a bacon butty? Under modern conditions of food preparation, pork is perfectly healthy to eat, isn't it?" Well, of course it is, and in so saying I told my questioner that I had many non-Jewish friends - and some Jewish ones - who habitually ate pork products and they all looked very healthy to me. Another question that comes up is brit milah - male circumcision - which (questioners ask) might have once been justifiable on health grounds, but not "in this day and age." As a matter of fact (I reply) there is compelling statistical evidence linking male circumcision to lower incidences of various maladies including penile cancer and (in partners) cervical cancer. But that is most certainly not the reason Jews circumcise their male offspring.

Brit milah, shechita and the laws of kashrut do not in fact have anything to do with health, but everything to do with faith.

It may well be that Jews are not permitted to consume blood (see, for example, Deuteronomy 12:23); but that has nothing to do with the manner in which we slaughter our food animals. This may come as a shock to Mr Parish and, if so, I have to admit that in the past some of our communal spokespersons seem themselves not to have appreciated the force of that argument.

We practise shechita, we refrain from eating certain foods, and we circumcise our male children because we believe they are divinely ordained. No further justification is necessary or appropriate.

But what I find sinister is that the said MP and his associates should have had the effrontery to tell me what is compatible with my faith. I would never dream of telling them what is compatible with theirs. In the case of Neil Parish, by all accounts a jolly farmer from the West Country, I might be persuaded into a forgiving mood. But the research carried out by Brewer and Osin strikes me as scientifically pointless and - therefore - morally questionable. They have a lot of explaining to do.