In November I participated in a debate held at the London Jewish Cultural Centre and billed as "a thought-provoking and provocative evening about the relationship between Jews, meat and shechitah (ritual slaughter)". The evening was undoubtedly thought-provoking and certainly provocative. It provoked me to think seriously about the phenomenon of Jewish vegetarianism, and about the underlying motives of those who propagate this dogma.

I was not invited to this debate: I invited myself (and paid the fee). Not to learn about vegetarianism, or to be told what I already knew - that a number of rabbinic luminaries (including Rav Kook, the first Ashkenazi chief rabbi of Mandate Palestine) - have voiced their sympathies with vegetarianism, or have indeed been vegetarians themselves. I went, primarily, to test my suspicion that an attempt is being made by Jewish vegetarians worldwide to ally the philosophy of vegetarianism to the precepts of Orthodox Judaism. In recent years I have noted this mésalliance with increasing concern.

True Orthodox Jews (it has been said to me) must be vegetarians. For reasons to which I shall allude, this strikes me as nonsense. I was to some extent prepared for this nonsense to be mouthed once more at the LJCC debate. But what I wasn't prepared for was the shameless manner in which those who purveyed it went about their work.

The evening began with the screening of the notoriously divisive propaganda film A Sacred Duty, made in 2007 by the South-African/American Emmy-award winning vegetarian Lionel Friedberg. The LJCC billed this as a "documentary" but, believe me, such a description is a travesty. Sacred Duty is certainly a slick production, professionally pandering to the obsession with imminent man-made environmental catastrophe that is one of the hallmarks of contemporary "green" politics. There's certainly a debate to be had about the extent to which global warming (which is a fact) is man-made. In teaching my own students about environmental politics I'm careful to present a balanced argument - pointing out (for example) that there was a period of equally undoubted global warming some 10,000 years ago, but that this could hardly have been due to fossil-fuel emissions (it was in fact the inevitable result of a periodic "wobble" in the rotation of the earth).

Friedberg will have none of this. His film blames all the environmental problems of the world on the evils of humankind. And the film leads, inexorably, to the "evil" of meat-eating, climaxing with scenes shot inside various slaughterhouses.

Those who have seen the Nazi propaganda film Der Ewige Jude will know that this Goebbels-inspired masterpiece of 1940 climaxes its denigration of Jews and Jewish values with an attack on shechitah. While I am not for one moment accusing Friedberg of being a copy-cat I'm afraid that I could not help bringing this to mind as I watched Sacred Duty. In one respect, indeed, Friedberg has stolen a march on Goebbels. Goebbels could not include in Der Ewige Jude statements by Jewish religious authorities agreeing that Jews were a sub-human pestilence worthy only of eradication. But in Sacred Duty we have interviews with Orthodox rabbis who not only refrain from eating meat themselves, but who tell us that keeping kosher can only mean being vegetarian. "I am a vegetarian," declares Rabbi David Rosen, CBE, "precisely because I am a believing Jew… I am vegetarian because I am a religious Jew."

Well, it's precisely because I'm a religious Jew that I am a meat-eater. I cannot speak for Rabbi Rosen, but when I say my daily prayers I pray for the restoration of the Temple and of all its rituals - including the slaughter of animals for sacrifice and their consumption after slaughter. I believe that when the Temple is restored we will - all of us (including Rabbi Rosen if he's still around) - be obligated to eat the Korbon Pesach - the Passover Sacrifice, just as did Jesus the Jew.

You won't find this view, which is the normative Orthodox view, in Friedberg's film. When I articulated it in the informal discussion that followed its screening at the LJCC I was - alas - met with derision that can only have been born of comprehensive ignorance as to the authentic tenets of Jewish religious Orthodoxy.