One of the curious aspects of modern life is the number of adults who never knew they were Jewish until well into their adulthood. It reflects the legacy of the Holocaust, as well as the shame that once greeted those who married out of the faith.

Joan’s story epitomises the latter case. She was in her 50s, had lived in her village in Suffolk for over 20 years and went to church once a month. She never considered herself a great believer, but enjoyed the hymns and found the sermons worthwhile.

It was still a great shock, though, when her mother lay dying and told Joan that she herself had been born Jewish and therefore Joan was Jewish, too.

Joan was staggered both at the news and that her mother had kept such knowledge secret from her. It emerged that Joan’s mother had run away from home when she was 18 to marry Joan’s father, who was not Jewish. Knowing she would be cut off from her family, she had decided she might as well leave behind her Judaism as well.

Joan, an only child, had been brought up nominally in the Church of England and had never had any contact with her Jewish family. However, as Joan’s mother’s final moments approached, she had felt it important to pass on the heritage she herself had neglected but never forgotten.

Joan was taken aback, but not entirely surprised. She had always been interested in Judaism, although she had never pursued it beyond making a point of watching Jewish programmes on television. She had also been conscious that she had felt drawn to the occasional Jewish people whom she had met over the years in a way that puzzled her.

Her mother’s revelation led to Joan starting a journey to discover her Jewish roots and “who I really am today”.

Jason’s experience involved a chance discovery. When his mother died, he started clearing the house she and his late father had lived in for almost 50 years.

He came across an old suitcase in the loft that he could not open as the lock had rusted. He eventually forced it open, upon which he discovered papers that astonished him.

Several had strange writing on them, which he later found out was Hebrew, while there were cuttings from a paper called the Jewish Chronicle, as well as a marriage certificate indicating a wedding that had taken place in a synagogue. It was his parents’ marriage certificate.

It was clear that Jason’s parents had both been Jewish but had decided not to pursue it. More than that, they had consciously eradicated all reference to their religious background while Jason was growing up.

Both parents had come to England from Germany at a young age, probably on the Kindertransport. Most of their mother’s parents had died in the Holocaust, while what remained of their father’s family had gone to live in Canada.

Jason reckoned that his parents had decided, in the light of their own terrible experiences under the Nazis, to try to shield their future children and grandchildren from possible recurrences of antisemitism.

He also began to realise that disparate parts of his childhood now made more sense: the lack of an extended family, his parents never having any religious identity and their dislike of discussing anything to do with Israel in the news.

Jason was fired up to learn both about Jewish history and Judaism itself. It eventually resulted in him joining a synagogue: “I felt it was important to reconnect with my history and this seemed the best way of doing that.”

From the Jewish community’s perspective, the key question is how we should react to those rediscovering their Jewishness, especially as both types of background are common and will have been replicated in other families.

When Jason first approached a synagogue to explore his Jewish origins, he was told he would be better off going to his local library and reading books on Jewish life. Joan was told that unless she had papers to prove she had a Jewish lineage, the rabbi would not be able to help her.

Such responses are not only dismissive and hurtful on a personal level, but a major own-goal communally. Such individuals should be greeted warmly. It is partly a matter of respecting their Jewish past and acknowledging that it gives them a right to a Jewish present. It is also about the Jewish community reclaiming its own.

Rather than being seen as a nuisance or suspicious, the rise of re-emerging Jews should be viewed as an opportunity to redress past losses. It also means that courses should be made available that provide a user-friendly guide to Judaism for adults. “Welcome home” signs should be erected. Facilitating their return should be a considered a modern mitzvah.

Dr Romain is rabbi of Maidenhead (Reform) Synagogue