In the unlikely event that David Beckham would have to flee Britain for his safety, he could find refuge in Israel. Since his mother’s father was Jewish, the former English football captain is entitled to settle there under the Law of Return, which enables the grandchild of a Jew to claim Israeli citizenship — although it does not confer Jewish status.

But that could be about to change in the fallout from the latest Israeli election earlier this month. As Likud leader Benjamin Netanyahu tries to stitch together a government, one of the demands of his prospective partner, Bezalel Smotrich, head of the Religious Zionism Party, is to amend the Law of Return by removing the so-called “grandfather clause”.

While the usual haggling over ministerial posts and policies continues, it remains to be seen whether a shift in the delicate balance between religion and state will actually happen. But the Orthodox religious bloc — consisting of United Torah Judaism, Shas and the Religious Zionism Party along with its electoral allies, Otzma Yehudit (Jewish Power) and Noam — has never wielded greater numerical strength, collectively matching the share of Likud MKs.

The religious parties regard the immigration of non-Jews under the Law of Return as a potential threat to the cohesion of Jewish society. And with war now raging in Eastern Europe, their number is likely to grow. According to the Jewish People Policy Institute, the Jerusalem-based think tank, whereas the core Jewish population in Russia amounts to 150,000, the number eligible to come to Israel under the Law of Return is four times that figure.

It is not the only potential change to the religious status quo. Itamar Ben-Gvir, leader of Jewish Power, has called for de-recognition of non-Orthodox conversion so that only those have adopted Judaism under the auspices of an Orthodox rabbi would be able to make aliyah under the Law of Return.

Such are the quirks of the Israeli system that for many years Reform and Conservative converts could emigrate under the Law of Return as long as the conversion was supervised by a rabbinic authority abroad, but not in Israel. That changed last year when Israel’s High Court, quashing the apparent anomaly, ruled that non-Orthodox conversions overseen by Israeli rabbis would also be valid for Israeli citizenship.

(Nevertheless, non-Orthodox converts are still unable officially to marry in Israel as the Orthodox rabbinical authorities do not recognise them as Jewish and there is no alternative to Orthodox religious marriage.)

The court ruling also broke the monopoly of the Israeli Chief Rabbinate, which until then had sole authority over Orthodox conversions, freeing other Orthodox rabbis to offer a more flexible approach to admitting converts.

While the number of non-Orthodox converts who make aliyah each year is tiny, the repercussions abroad would be significant because of the symbolic impact. It would be seen as deligitimising the Progressive and Conservative movements, which comprise the majority of synagogue-affiliated Jews in the largest diaspora community, the US.

Doron Almog, head of the Jewish Agency, which manages the aliyah process, has warned against tinkering with the Law of Return. “We believe that it is critical to ensure our relations with world Jewry remain intact,” he said. So too has the deputy chairman of the World Zionist Organisation, Yizhar Hess, who said the Law — which has remained in its current form for more than 50 years — represented the “DNA of the Zionist movement… You don’t slam a door in the face of your family”.

Orly Erez Likhovski, head of the Reform movement’s Israel Religious Action Centre, denounced “dangerous demands” that would cause an “irreparable rift” with the diaspora.

But the Sephardi Chief Rabbi Yitzhak Yosef brushed aside the opposition, saying that “Israel was an Orthodox state, not a Reform one”.

The more secularist Likud will be warier of picking a fight with American Jewry, particularly amid signs already of growing estrangement. According to a survey by the American Jewish Committee, more than 40 per cent of Jewish millennials do not consider ties with Israel to be important. “Israel’s legitimacy as a Jewish nation-state is dwindling and attitudes toward the state are increasingly critical and harsh,” the JPPI said in its 2022 synopsis of world Jewry. A new battle over who is a Jew would hardly ease the strains.

Conversely, there is a school of thought that sees the Jewish future as Orthodox, encouraged by the remarkable growth in particular of the Charedi community compared with what appears as high assimilation elsewhere. From this vantage point, strengthening the place of halachah in the governance of Israel might seem a far-sighted move.

As it is, up to a half million Israelis live in a state of limbo, immigrants under the Law of Return who are not considered Jewish. Attempts to liberalise halachic conversion in Israel have largely failed in the past; even so, many of them would see no reason to convert.

Their children may be educated in a secular Jewish school, serve in the Israeli army, meet a Jewish partner, raise a Jewish family (even if unable to be married in Israel) and adopt Jewish customs. For all intents and purposes, they would live like many other secular Jewish Israelis. This could be viewed as a kind of reverse assimilation — not that the Orthodox religious parties would see it that way.