This year marks the centenary of the founding of the Liberal Jewish Synagogue. The LJS was established by - and owed its survival beyond a difficult birth to - a partnership between the gentleman scholar, Claude Goldsmid Montefiore, and the woman who wanted desperately to be his wife (but whose advances he rebuffed), Lily Montagu.
Montagu courageously gave up her chance to inherit a fortune from her father (the mega-wealthy and very Orthodox banker and MP Samuel Montagu) in order to act as the founding mother of the movement and of the synagogue that grew out of it. But I doubt very much that, if Lily or Claude were to visit the LJS today, they would recognise its ethos as bearing more than the merest resemblance to the movement as they envisaged it.
Montefiore was a theologian who had no time for Jewish Orthodoxy and for the talmudically ordained rituals and minutiae with which Orthodoxy had clothed itself. He was also a fanatical anti-Zionist. In common with most of the Anglo-Jewish aristocracy a hundred years ago, he regarded any assertion of a separate Jewish nationalism as a potent threat to the legal status and public standing of the Jews in this country, or indeed in any country of the diaspora in which they happened to dwell. In later life, he went so far as to place the blame for the rise of Nazism on the shoulders of the Zionist movement. As first rabbi of the LJS he appointed the American, Israel Mattuck, whose views on Zionism coincided with his own.
What interested Montefiore was the establishment of a Judaism that was de-ritualised and de-nationalised. What interested Montagu - apart, that is, from being as physically close to Montefiore as she could possibly get - was to reach out to non-observant Jews and to offer them a Judaism that elevated English at the expense of Hebrew and which offered women an equality with men in the running of a synagogue and its devotional activities.
In an important sense, the establishment of the LJS must be understood as a component of the wider Jewish feminist movement that was growing ever more confident - and more militant - at that time. In 1944, Mattuck inducted Montagu as a lay minister, the first woman to hold a formal religious office in any synagogue in this country.
You might argue that, at least in this regard, the Liberal Jewish movement has remained loyal to its founding vision. Today, the LJS pulpit is occupied by Alexandra Wright. In all, women account for almost half of those holding rabbinical positions in the movement in this country. But the anti-Zionism that was a founding hallmark of the LJS has been long since abandoned.
In 1976, the World Union for Progressive Judaism, which Montagu and Montefiore had helped create a half-century before, became the first international Jewish religious association to join the World Zionist Organization. As Rabbi Wright admitted in last week's JC, Liberal Jews now place much more emphasis upon ritual than Montefiore would have approved of, and are keener to emphasise the historical and purely Jewish foundations that underpin their faith.
As far as Montefiore was concerned, to be a good Jew was simply to bear witness to "righteousness in action and truthfulness of the heart" - nothing less and nothing more. But today the movement is rediscovering, in some measure, its Orthodox antecedents.
Which brings me to the appointment of Baroness Julia Neuberger as senior rabbi of the West London Synagogue.
A hundred years ago, the West London - the UK's first Reform synagogue - was, in its theology and its ritual, little different from some of the more radical "centrist" Orthodox congregations.
It would have no truck with Liberal Judaism, which indeed it went out of its way to condemn (inter alia on the grounds that men and women should not sit together and that hymns should not be sung if composed by non-Jews).
This past is clearly dead. Rabbi Neuberger comes from a Reform background but is herself a Liberal Jew who four years ago became president of the movement in the UK. She is an accomplished speaker. And she sits in the House of Lords.
While talk of her evolving into a non-Orthodox alternative "chief rabbi" - or even (as The Times menacingly hinted) "de facto leader of all of British Jewry" - is wild exaggeration, her latest appointment marks a distinct and I suspect irrevocable turning-point in the expansion and growing self-confidence of the non-Orthodox movement in this country.