“Judaism 1” really exists. It is the religion of about 300,000 people in Britain and perhaps 13 million worldwide. “Judaism 2” is an imaginary religion, created by Christian scholars for ideological purposes.

As a teenager I remember being puzzled on learning that Jesus was born a Jew, but that his coming put an end to Judaism, which in any case was an outmoded, worn-out religion of hair-splitting laws and meaningless rituals. If Judaism came to an end nearly 2,000 years ago, then what was I? Some kind of fossil? And was my religion really ritualistic, legalistic, passe? As a progressive Jew belonging to a Reform synagogue I certainly did not think so!

That was years ago and perhaps things have changed. Or perhaps not. My daughter, when she was 11, was so unhappy at the presentation of Judaism in her secondary-school RE class that I withdrew her from it, although I am in principle against withdrawing children from RE classes - or any other classes for that matter - because I cannot see any reason why anything should be taught in our schools that is suitable for some pupils but unsuitable for others.

The problems arose not in the study of Judaism but of Christianity. It was a case of “the two Judaisms” again.The Old Testament was presented as Christian scripture, preparing the way for the New Testament and prophesying Christ. It was also implicitly devalued by comparison with the New Testament, which was supposedly given to complete or perfect the older teachings. This structure was not flagged up as a specifically Christian teaching, let alone as being contrary to historical criticism or offensive to Jewish susceptibilities, both of which it is.

RE specialists give the name “super-sessionism” to the teaching that Christianity superseded Judaism. It is a harmful, historically false teaching and ought to be eradicated. Apart from anything else, it is bound to lead to confusion when students come to study Judaism as a living religion. As a general rule, it is essential that RE teachers should distinguish clearly in their minds between objective facts and the teachings of specific religions. Obviously this is particularly important where the teachings of one religion are offensive - deliberately or unwittingly - to adherents of another. It should not make any difference whether or not there are members of the religions in question in a class. It is all too easy to perpetuate prejudices and the results can be catastrophic.

Dr Nicholas de Lange is reader in Hebrew and Jewish Studies, University of Cambridge, and author of ‘An Introduction to Judaism’ (CUP)