John Rayner, who has died aged 81, was the epitome of the cultured English gentleman - erudite, beautifully spoken, imbued with the classics, languages and history. He was also a rabbi, but without a beard or a hat. For 20 years, he was the head of the Liberal and Progressive movement in Anglo Jewry, a quiet voice for what was the most radical wing of the religion in Britain.
Not that he was not controversial. His attitude to Israel, for instance, was, at best, ambivalent, and some people took his Angloism to be a little too close to Anglicanism. Likewise, his opposition to a resurgence of tradition at the Liberal Jewish synagogue in St John's Wood, north London, was seen by some as a kind of eccentricity.
Rayner was born Hans Sigismund Rahmer in Berlin, and came to Britain with one of the last kindertransports of Jewish children in 1939. Five years later, after leaving Durham school, where he was house captain of athletics, he changed his name to John Desmond Rayner. It helped him when he was commissioned as a captain in the Durham Light Infantry during the second world war. He won an open scholarship to Emmanuel College, Cambridge, and took a BA in moral sciences and modern languages, and the Glover prize for Hebrew. While studying, he served as unofficial Jewish minister to the town.
When he began his ministry, at the South London Liberal Jewish synagogue in Streatham in 1953, the Liberal movement represented an exceptionally bland form of Judaism. Some said it was a religion of convenience: you came to Rayner's synagogue with or without hats, to suit your taste; the services were almost entirely in English, and those who attended did so as a kind of identity with their own past, if they did it regularly, or simply because they saw it as the easiest way of practising their religion when the occasion - such as a wedding or Yom Kippur - demanded.
Rayner carried on most of that tradition, although he was a Hebrew scholar and a Bible and Talmud expert. He resented the idea that the Liberal synagogue was a movement of convenience and ease. But he was never a visceral opponent of intermarriage and, unlike the Orthodox synagogue, encouraged the conversion of non-Jewish partners. In 1949, he had written to the Jewish Chronicle, "There is no reason whatever why diversity of worship should lead to disunity."
It was while at Cambridge that Rayner had experienced from the inside his first communal dispute, when he introduced "progressive" services at the local synagogue. A year later, he would say: "The differences between Orthodox and Liberal Judaism are not trivial. The adjectives are designed to draw attention to that fact. But the common noun points to the common ground."
At his South London ministry, he was a vocal opponent of Jewish nationalism which he termed "Noachism", and which, he said, showed "some" concern for non-Jews, but not enough. Orthodoxy, on the other hand, he said, was too concerned with ritual. For that reason, his synagogue did not insist on circumcision, nor did his boys celebrate barmitzvahs.
In 1957, Rayner became assistant minister and, in 1961, senior minister of the rather austere Liberal Jewish synagogue in St John's Wood Road. Four years later, he had a two-year sabbatical to take a postgraduate course in rabbinics at the Hebrew Union College/ Jewish Institute of Religion in Cincinnati, before returning to St John's Wood and his writings and lectures on his kind of Judaism. Orthodoxy, he believed, was too often Judaism "without content. Humanistic Judaism I would like to see perpetuated. If an individual Jew does not believe in prayer, in organised religion or religious ritual or observance of any kind, but is quite impressed by what he reads of Jewish literature, if he feels quite inspired by certain episodes in Jewish history and this he would like his children to know about, I would certainly encourage and welcome it."
As a Liberal, Rayner was said to be on the leftwing in Jewish terms. He was that in national politics, too, and made a number of speeches condemning Enoch Powell after the Conservative MP's "rivers of blood" speech in 1968. "Our own security and welfare as Jews is bound up with a liberal attitude on part of the British public towards immigrants new and old," he declared. "Our duty as Jews is to proclaim again and again that the perfect society is not one of dull uniformity or spineless conformity, but an association of diverse individuals and groups." This pretty much summed up his attitude to his religion, too.
When, in 1991, the Chief Rabbi, Jonathan Sacks, refused to take part in a radio discussion with a Reform (not Liberal) rabbi, Rayner condemned his decision as "outrageous, preposterous and inexcusable" - a statement contested by other Progressive rabbis who did not seem to mind as much as he did.
Rayner became minister emeritus at St John's Wood in 1989. He was chairman of the World Union for Progressive Judaism. In 1994, he became the first president of the Union for Liberal and Progressive Synagogues, a tribute both to his synagogue work and his writings. He was co-editor of the two Liberal prayer books, The Service of the Heart and The Gate of Repentance. Among his books were The Practices of Liberal Judaism (1958) and Towards Mutual Understanding between Jews and Christians (1960). He was co-author of Judaism for Today (1978) and The Jewish People: Their History and their Religion (1987).
He married Jane Heilbronn in 1955. She survives him, as do their two sons and one daughter.
· John Desmond Rayner, rabbi, born May 30 1924; died September 19 2005