Of the many Holocaust-era memoirs, there can have been few such as John Carr’s Escape From The Ghetto. For not only is it a true story, but it is the story of John Carr’s father — and its uniqueness lies in Carr’s decision, at the suggestion of his first publisher, to tell Chaim Herzsman’s many adventures as though he himself were the protagonist.

The decision to tell the story in the first person lends an immediacy to the story which draws the reader in — and is all the more extraordinary because, as Carr readily reveals, his was a difficult childhood and adolescence, and for years he did not get on with the irascible man who had become known as Henry Carr. “It was a terrible relationship”, he says.

But once the Yorkshire-raised John Carr, the eldest of Henry’s five children, won a place at the LSE and was looking for somewhere to live in London, the dynamics of the relationship changed. Henry, now divorced from John’s mother, had a large flat in Soho and offered John a room in it.

It was 1971 and the opportunity to live rent-free, walking distance from LSE, was too good to pass up. And so, slowly, John Carr began to get to know his father, putting together what had happened to the former Chaim Herzsman since he was a boy of 14 in Poland.

Carr freely admits that his motivation for writing his father’s story was “a process of self-therapy”. And by researching and recording his father’s helter-skelter years on the run from the Nazis, John Carr felt he was better able to understand why his father had found it so difficult to be a warm and loving figure to his five children. He found out why there were so many family secrets, too.

“We knew absolutely nothing of his story when we were growing up. It was only after the divorce that we learned some of what had happened. For example, we all thought he was a Catholic — we were all Catholics — and he didn’t go to Mass with us on Sundays.

“When I asked my mother why he didn’t come with us, she said that he went to the Polish Mass. We lived in Leeds, there was a big Polish-speaking community, so it was entirely plausible — and it maintained the lie that he had told about being a Catholic”.

Carr doesn’t even know if his father did go to the Polish Mass, but now assumes not.

Odd things happened as the Carr siblings were growing up. “My dad never gave up on finding out what had become of his family. Eventually, in 1957, he found that his older brother, Nathan, had survived and was living in Israel. He wrote to him via the International Red Cross, I think, and insisted that he should come to England to visit, offering to pay for the trip”.

There was one condition, however: “Dad told Nathan that he had to present himself as a Catholic called Michael Karbowski. He was to say that he had married a Jewish woman whom he had met in a Displaced Persons’ camp after the war, and that’s why they were living in Israel”.

Nathan agreed to this charade: John Carr says his uncle was aware that many Jews had survived the war by masquerading as Christians. He was somewhat bemused that his brother was continuing the pretence, but said “OK, if that’s the way you’re living, I’ll go along with it”.

So “Uncle Michael” came to Leeds and stayed with the Carr family in the Headingley neighbourhood for a few weeks. “And after he went home the Polish Catholics in the area came to my mother and said, he’s not a Catholic, he’s a Jew. And if that’s the case, Angela, your husband is a Jew, too.”

Carr hastens to add that identifying her husband as Jewish — she had not asked him a direct question about his religion — was not a factor in the divorce, which was eventually finalised in 1963. Nor, he says, did the family have any contact with the Jewish community in Leeds during his upbringing. “All my cultural roots are connected with Yorkshire and the world of Irish Catholics.”

Carr’s parents had met in Glasgow when Henry Carr was training to be a tailor’s cutter for a Jewish company, Winetrobe. Angela Cassidy was studying to be a seamstress and the two met at technical college. The couple moved to Leeds after their white-hot affair resulted in her pregnancy, and they were married — and Henry baptised — under Catholic auspices.

Learning about his father’s true background was a slow and difficult process, Carr says. “Initially, he didn’t want to talk. I think he was embarrassed that he had lied to his Catholic children and he thought we would be resentful. But that wasn’t the case at all. In 1972 I went to Israel and saw what I now know to be my uncle Nathan. The following year I went to Poland.

“Eventually my dad came to understand that his children were cool about this whole Jewish thing, we just wanted to get to know him better”.

The turning point for John Carr came in 1988 when he travelled to Lodz to meet, for the first time, one of his father’s cousins, Heniek. “We met at the Jewish community offices in Lodz with the aim of going to the cemetery to see where our relatives were buried. And I said to Heniek, what exactly happened on the day my father escaped from the ghetto?”

Heniek related the terrifying story of how the 14-year-old Chaim had accidentally been caught outside the Lodz ghetto walls while he, Heniek, was inside and watched in horror as Chaim’s younger brother, Srulek, became caught on the barbed wire. A guard came along to investigate and Chaim, feeling he had no choice, stabbed him — and then took to his heels and ran.

Heniek’s account dovetailed so exactly with that of Henry Carr’s that it galvanised John to begin as much documented research as he could, working out where his father had been, one step ahead of the Nazis, in terrifying years across war-torn central Europe.

“I have records of him in the Lodz ghetto, I have records of him in a Jewish refuge in Vichy France en route to Spain and Gibraltar, of him arriving in Gibraltar in 1943, of him joining the Free Polish Army in London in March 1944, of him transferring, when all the Polish Jews transferred, out of the Polish army into the British army… so I was able to anchor the story through verifiable public documents that anyone could inspect. But of course, a great deal of it is what he told me”.

John Carr is a long-time Labour politician — his wife is Baroness Thornton, shadow health minister in the Lords — and by profession he is an internet security expert and a former senior visiting fellow at LSE. Though he has written many pamphlets and academic material over the years, he has never written anything like Escape From The Ghetto, which, he says, he wanted to write for his children’s benefit, so that they should know about their grandfather’s life.

Henry Carr died in 1995, a survivor against the odds, thanks to a combination of near-Aryan good looks and white-blond hair, quick thinking and an enviable flair for languages, which allowed him to work as a translator and to pretend to be anyone — except a Polish Jew.

Escape From The Ghetto, by John Carr, is published by Hodder at £20