My parents grew up in the United Synagogue. I grew up in the United Synagogue. And I have had the distinct privilege of serving as rabbi of a United Synagogue community for ten years. Yet, all that is nothing compared to the grand sweep of history encompassed by the 150 years that have elapsed since the founding of the organisation.

As the US celebrates its special anniversary this month, there are many things it can be proud of. It has remained true to the mission set out by its founding fathers, a unified community of synagogues that would always welcome all Jews, whatever their background or level of observance. To this day, it continues to seek out new areas of Jewish growth. And it supports key institutions of British Jewry such as the Office of the Chief Rabbi, the London Beth Din and the London Board of Shechita.

But, above all, this is a time to focus on the remarkable historical contribution the United Synagogue has made to British Jewry over multiple generations. And at the heart of that contribution lies one simple truth. The US has, almost single-handedly, kept British Jewry Jewish.

In his essential book on the United Synagogue, Community of Faith, Rabbi Sacks cites a vital observation of the leading 20th century social scientist, Professor Charles Liebman. Commenting on the state of American Jewry in the late 1960s, Liebman argued that it would be a grave mistake to think of assimilation in terms of individual Jews abandoning their Jewish identity. Because there can also be a far more serious “structural assimilation”, in which a Jewish community as a whole loses its “character and content”.

When that happens, the consequences for the entire community are severe. If the basis of collective Jewish identity becomes secular or social-cultural, rather than religious, or Torah, centric, the community risks losing its entire identity en masse, gradually sinking beneath the waves of the alternative options thrown up by the dominant surrounding culture.

Simply put, Jews need grounding in authentic, traditional, Jewish values and practices in order to stay Jewish. And Jewish communities need to remain committed to those authentic practices in order to help their Jews stay Jewish. And that mission is one that the US has steadfastly and resolutely stuck to, generation after generation. Like a ship tossed in those stormy waves, it has often leaned to one side or the other, sometimes looking dangerously off-kilter to both the right and the left, but it has somehow always regained its balance once more in the end. With the passing of each new challenge, the US remains on the sea, sailing ever forward towards its immutable goal of providing a religiously authentic Orthodox grounding for British Jewry.

And the result? The result is nothing less than generation upon generation of Jews in this country who have grown up with the knowledge that they will be born, marry, give birth and die in an authentically Jewish, halachically-sound way.

They have journeyed through life knowing that, although their personal observance may wax and wane through life, they will only ever feel at home in a shul that looks like, feels like and prays in the manner of the shul their grandparents and great-grandparents knew.

At each major milestone in their personal and family lives, it is to their local US that they have turned to help them celebrate or commemorate that event.

And when eventually their time comes, their last wish is to be buried in a traditionally Jewish way, which for so many has meant once again turning to the US.

Without the US, the Jewish community in this country would undoubtedly be more fragmented. It would consist of many more different groups and gradations of religious observance. Some might have welcomed this diversity and freedom of expression rather than uniformity and consistency.

But the experience of other countries across the Jewish world, particularly in America, demonstrates that this comes at a steep price. Without the US, the Jewish story in the United Kingdom, a more secular country than the United States, would unquestionably have been one of deep-rooted structural assimilation. A community on its way towards losing the very “character and content” that forms the basis of its identity.

Instead, thanks to the US, the British Jewish community has retained a sense of direction and commitment. It has remained, in the broadest sense, authentically and traditionally Jewish. And that is a legacy of which the US should be tremendously proud as it celebrates this remarkable milestone.

Yoni Birnbaum is the rabbi of Hadley Wood United Synagogue