On paper, it makes sense. Marry out and you’ll raise children who are less engaged in Jewish custom, practice and thought. This is a disaster for Jewish continuity. We will assimilate ourselves out of existence.

But real life can get in the way of theory. We all know people who are 100 per cent Jewish but who have zero interest in either Judaism or Jewishness and no feelings of connection with their fellow Jews. The beautiful tapestry of Jewish civilisation — our literature, our music, our humour and our food — these treasures built up over millennia leave them cold.

And in some cases, it’s even worse — we’ve all met self-hating Jews, people who are ashamed of being Jewish while being halachically Jewish..

There are Jews with just one Jewish parent who identify very strongly indeed. And then there are those with backgrounds like mine. I have two Jewish grandparents — my dad’s father and my mum’s mother —and I feel Jewish with every fibre of my being.

But although I’m kosher for the Orthodox, I don’t subscribe to halachah. If my family tree had grown differently and I’d been born with a Jewish grandmother on my dad’s side and a Jewish grandfather on my mum’s, I’d feel as I do now. For me, being Jewish is not about the illusory purity of the matrilineal line or the biography of the person with whom you make children. My children’s father is a Catholic-raised Sicilian which means there are now more leafy branches on my family tree. But this hasn’t diluted my children’s sense of identity. They feel as Yiddishe as I do. It is in our psyche and the marrow of our bones. Jewish continuity happens in myriad ways.

Rivka Bond understands. She’s the author of Speechless, a novel about what might happen if state antisemitism ever become official policy in the UK. One reviewer said of the novel that the “resonance with The Diary of Anne Frank is unmistakeable.”

Bond feels very Jewish indeed. And yet she has married out. She understands the prohibiton but is ambivalent about it pointing out, “if, for whatever reason, a non-Jewish partner doesn’t want to convert, they can still commit to gaining some Jewish learning and to supporting a home that is rich in Jewish tradition and practice.”

Her husband has gone a few steps further. Bond grew up in a secular home, but became “more Jewish”, as she puts it, after the 2014 Gaza war when she discovered that many of her friends held antisemitic notions that became excruciatingly evident on social media. It was a very painful period but her non-Jewish spouse provided the staunchest support she could have wished.

“He began reading the Jewish papers and he went with me to rallies against antisemitism. He bought a kippah, we attended Jewish events together and he embraced my new ritual of lighting Shabbat candles.

“And we both now have Israeli citizenship. We’ve accepted that a Jew can never have too many passports and that goes for the family. Whatever happens next, we’re in this together.”

We’re in this together… For me, this is what being Jewish comes down to. If you throw your lot in with the Jews, you become Jewish by osmosis. It is why I am so supportive of Israeli politican and scholar Yossi Bellin’s proposal, first floated in the 1990s, for secular conversion. In his book My Brother’s Keeper he argues that it is absurd that in the 21st century, a time when most Jews are not religious, that the only way to become Jewish is through the turnstile marked faith. Put another way, why must a non-Jewish atheist go to a rabbi to become a Jewish atheist.

Mark feels this irony keenly. There was never any question his non-Jewish, staunchly atheist, wife would convert and yet she is very supportive of his Jewish life, expressed in part at Finchley Progressive Synagogue where he is active, sometimes with his wife by his side. “It’s certainly always her who reminds me when the Jewish festivals are coming up!” he says.

But it took him a long time to take the walk down the aisle with a non-Jewish woman. “I didn’t get married until I was 41. I was brought up in a Jewish household with a strong expectation that I’d marry in and in my 20s and 30s, it meant I stopped relationships with non-Jewish women from going too far. I was always looking for a long term Jewish partner.”

Now in his late 50s, he expresses regret that he felt he couldn’t follow his heart earlier. “I wasted a lot of time. I was carrying a big psychological weight which has now been lifted.”

When he did get engaged —“the balance finally tipped in favour of my personal happiness over family expectations” -- the circumcision issue loomed large.

“Before she was pregnant my wife made it very clear that if we had a boy he wouldn’t have a brit. At the time I was very bothered by this but once I’d accepted it was a condition of our having children together, I got over the hump. I now wonder why it ever felt so important .”

I agree. I have a father and brother who are proof that an intact foreskin doesn’t dilute your identity one iota. As it happens, Mark’s son, now in his late teens, feels indifferent to his Jewish heritage, but that’s not because he didn’t have a brit. It’s because however we steer our children there are no guarantees on how the plot of their lives will turn out.

Hilary Freeman is good example of this truth. She was raised in the bosom of the United Synagogue: an Orthodox primary education followed by a bat chayil, Bnei Akiva and an FZY Israel tour. In fact, she was so immersed in Orthdoxy that at the age of 13 she became more frum than her parents, refusing to turn on lights during Shabbat and tearing up toilet paper into sheets before it came in. “My line was I’m going to do this properly. Otherwise, I’m a hypocrite.”

At the age of 15 she expressed what she now describes as sanctimonious disapproval at the percentage of Jews who marry out. But at the age of 18 after dating exclusively Jewish boys during her teens, she had what would be her last Jewish boyfriend.

When she went to university Freeman started to question the Jewish rituals that punctuated her life. “I fasted on Yom Kippur and I still lit Friday night candles but afterwards I’d go to the union bar. There were only three Jews in my year and I felt I fitted in with my non-Jewish friends. Plus, I was studying the most questioning subject of them all — philosophy.”

It wasn’t long before she fell for a non-Jewish guy on campus. “He was really fascinated by my ethnicity, but because he wasn’t Jewish he didn’t feel welcomed by the Jewish community, and over time his fascination turned to antipathy.”

Like me, Hilary disapproves of this cold shouldering. “I hate excluding people because they are either not Jewish or not Jewish enough. It’s one of the many problems I have with Orthodox Judaism and one of the reasons I’ve rejected it.”

But she hasn’t rejected Jewishness. “I feel incredibly Jewish and I stick my head out as a Jew. When I’m with non-Jews I always talk about being Jewish and big our culture up, and am vocal about antisemitism. And I certainly couldn’t be with someone who was not interested in this part of me – my current partner is very happy to support me, and to raise our daughter as culturally Jewish.

“But I don’t need to be with someone Jewish to be me.”

That’s how I see things too. There’s no conflict between feeling strongly about your Jewish identity and being with someone non-Jewish. It’s a much more of an individual matter.