Of all the public figures whom you might think of to represent the Jewish community in a programme about religious belief, Edwina Currie, the former Conservative MP and junior health minister, might come very low on the totem pole.

And yet the one-time politician, now an established novelist and frequent reality TV broadcaster, gives a punchy performance in BBC2’s newest Pilgrimage series, this time tracing an ancient walking route to Istanbul via Serbia and Bulgaria.

Pilgrimage: The Road to Istanbul — three hour-long programmes which start on March 27 — features two Muslims, one, broadcaster Mim Shaikh, devout, and TV presenter Amer Latif, who is blind, a non-observant Muslim; two Christians — one a convert to Catholicism, broadcaster Adrian Chiles; the other, Olympian Fatima Whitbread, a practising Christian; and two representative atheists, the lapsed Catholic actress Pauline McLynn, best known as the housekeeper in the Father Ted comedies; and actor and comedian Dom Joly, who cheerfully despises all organised religion.

And then there is Currie, the former Edwina Cohen, brought up in an Orthodox Jewish family in Liverpool but who married out — twice — and for the first marriage, to Ray Currie, was cast adrift by her family. Her second husband, retired policeman John Jones, was fixed with a beady eye by Edwina’s mother before their wedding. She pronounced that she was “sure John had Jewish blood in him”, and, in the background of our phone conversation, John can be heard warmly guffawing.

Asked quite why she was on the pilgrimage as the sole representative of the Jewish community, Edwina laughs and says it’s because actress Miriam Margolyes took part in the last series.

More seriously, she says, the itinerary took in countries which she hadn’t visited before. “I hadn’t been to Serbia before. I’d been to Bulgaria, briefly, on the coast, and ditto to Turkey. But I liked the idea of a group of us from different backgrounds walking along, a bit like Chaucer’s Canterbury Tales, and talking and learning from each other. I also liked the idea of it being called a peace trail.”

She says she felt “very comfortable” as the “token Jew” in the group, but also felt curious. “There used to be sizeable Jewish communities in Bulgaria, in Turkey, not so much in Serbia. My family is Ashkenazi, one side from Ukraine, one side from Poland. So this was part of the world where there’d been big and successful Jewish heritage — but one that I was not familiar with. I thought, right, opportunity to find out, and to share that knowledge with the wider world.”

Physically, Edwina’s determination to tackle quite challenging terrain is extremely impressive, though there are occasions on which the 73-year-old says quite flatly “I’m not doing that”, whether that is scrambling up a terrifying mountain ridge or pushing herself through a “saint’s cave” in order to be judged “pure in heart”.

Part of her motivation for taking part, she says, was hoping to focus on “the extraordinary range of the history of European Jewry”, and wanting to tell their stories. So we see Edwina — and Pauline McLynn — at a very little-known Serbian concentration camp, Nis, set up in 1941 and eventually liberated by Yugoslav partisans in 1944. It barely qualifies as a religious experience in the strictest sense, but Edwina says it was an opportunity for the participants to “connect on all sorts of different levels, and listen to each other — it was fascinating”.

Nevertheless, Nis formed part of her most uncomfortable experience during the trip. There had been a lunch the day before in which the local priest was “going on and on about how Serbia had always been on the right side of history. And the next day we went to the camp: and I thought, you know what, you’re telling me that nobody nearby knew what was happening here? That did not sound right to me. Serbia had 12,000 Jews before the war, and afterwards there were a few hundred. They made a very good job of killing their Jews, they didn’t export them, they killed them on the spot”.

In another section of the films, Edwina and Dom Joly venture into a disused synagogue in Samokov, Bulgaria — built by a rich Jewish family for their own use and the benefit of the local community. The family, the Arie family, had moved from Vienna and their exquisitely furnished house, abandoned when they fled advancing Nazis, is now a perfectly preserved local museum. (The family survived and ended up in Israel, along with a sizeable Bulgarian community).

There is almost nothing left of the synagogue now — the floor is rubble — but high on the wall is a painted panel of Hebrew and Edwina — improbably, but rather charmingly — begins to sing Oseh Shalom, He who makes peace in his high places. It’s plainly something she learned as a child in Liverpool, that stayed with her, though John growls from the back of the room that it’s something they sing in their local choir in the Peak District where they live, another slightly surreal concept.

She describes representing Judaism to her six fellow pilgrims as “quite a responsibility” — though what she has learned for herself, she says, is that she doesn’t like churches with lots of pictures of saints. “I don’t believe in saints or magic — for me religion is more to do with community, and family, and how we treat each other.”

Her other main “takeaway” is that “it’s ok to argue and disagree. We were cool with that, thought it was very healthy”. Given that the seven participants are forced to share rooms on their two-week pilgrimage, getting on with each other seems paramount.

Edwina came back from the trip “strengthened” in her Jewish identity, more aware of the complexities of Jewish history and its outcomes. She draws a comparison between the fate of Serbian and Bulgarian Jews — 49,000 Bulgarian Jews at the outbreak of the war, 44,000 at the end. “The atmosphere in Bulgaria for us was so different, they were welcoming and hospitable. In Serbia, all they wanted to was to tell us their side of the story”.

Pilgrimage: The Road to Istanbul begins on March 27 on BBC2.