When Nick Broomfield decided to make a film about his family, he didn’t quite realise just how tricky it was going to be. “It’s very difficult doing something that you’re so close to,” he says, speaking on the phone from Los Angeles, “because obviously you could get into very, very intimate stuff, which might not mean anything to an outside audience. At the same time, I found it much harder than most films to really assess at what level to tell the story. You want to have personal things in it.”

With five decades’ experience making documentaries, it’s intriguing hearing the British-born filmmaker admit to vulnerability when faced with a project. Alongside Michael Moore, he’s probably one of the most recognisable documentarians in the world, thanks to the period in his work where he increasingly appeared on screen — in films like Tracking Down Maggie (where he pursued ex-PM Margaret Thatcher for an interview) and Kurt & Courtney (ditto, rocker Courtney Love).

In his latest film, My Father and Me, Broomfield,73 explores his relationship to his dad, Maurice Broomfield, who came from a tough working-class Derbyshire upbringing but emerged as one of the pre-eminent industrial photographers of mid-20th century Britain. Showcasing factories and workforces, his stills beautifully capture long-gone elements of post-war industrial Britain. They are set to be the focus of a V&A Museum exhibition in the autumn and a book, Industrial Sublime.

“As a kid, you grow up just in a slightly unthinking way… you’re always surrounded by these photographs,” Broomfield says. “You’d never think much about how they were unique or different.” Until the V&A stepped in, many of the negatives were in terrible condition; now thousands of photographs have been preserved in cold storage, many of which Broomfield had never seen. “It was a real pleasure, just seeing how remarkable a lot of his pictures were.”

Yet despite the title, My Father and Me evolved into something deeper even than a look at his father, who died in 2010 aged 94. Using a wealth of home movie footage, Broomfield also explores his relationship to his mother, Sonja, a Czech-born Jewish refugee whose family escaped her birthplace during the war. As he reveals in the film, Broomfield didn’t know he was Jewish during his childhood. “I honestly never went to synagogue,” he tells me. Instead, he was raised Quaker, his father’s persuasion.

“It was a very strange thing,” he reflects, “because I do remember moments in my childhood when I was growing up [in London’s Parliament Hill]. I remember the neighbours... they were called the Tumblers. They were a very Jewish family, as was our doctor who lived next door. And they both said to me, ‘You’re Jewish.’ But when I asked my parents about it — my mother in particular — there was a complete sort of denial. The war was so traumatic, and that sense of persecution was so embedded, that they just wanted to start a new life.”

Broomfield understood his mother’s denial of her roots once she arrived in Britain. “I think, quite a lot of Czech-Jews did the same thing. I always remember [American politician] Madeleine Albright, who was from a Czech-Jewish family as well… saying that she didn’t discover until she was in her twenties about her background at all, and I’ve come across other people [like that]. So I think it was a relatively common thing: we’re citizens of the world and we’re just making a new start.”

It was only when he went to New York in his twenties, staying with his aunt — one of his grandmother’s sisters — that he found out about his Jewish heritage. “She told me the real family history in a kind of uncensored way. And I used to spend hours talking to her in this teeny apartment on West 73rd Street and found out the true story of my family, and what they’ve been through.”

As Broomfield explains in the film, there were disagreements and fallings out within his family too. His parents’ in-laws didn’t exactly see eye-to-eye. “Working class English who didn’t like foreigners and Jewish foreigners who didn’t like the biases of the English,” he narrates. “It’s not surprising the two families would never really understand each other.” His mother’s family had lost a number of people in concentration camps — and didn’t share his father’s pacifist outlook.

There are clips featured of Broomfield’s grandfather on his mother’s side, whom he called Gogo — a left-wing intellectual who was with the British army when they liberated Belsen concentration camp in April 1945. Gogo and Maurice clashed years later, when Broomfield’s grandfather gave him Edward Russell’s book, Scourge of the Swastika, which detailed Nazi war crimes. Maurice had been a conscientious objector during the Second World War and worked with the Red Cross in Germany after the war.

I wonder if it took time for Broomfield to reconcile with the decision by his mother, who died in 1982, to bury her Jewish roots. “I think in my mother’s case…she and my grandfather had both been members of the Communist Party until the early 50s, the invasion of Hungary. And they were very, very committed socialists, which I guess was anti-religion anyway. I think they were both very anti-religion in all its forms. So I kind of understood it more, probably from that point of view, I think.”

In My Father and Me Broomfield analyses his parents’ influence on his own work — films like The Leader, His Driver and The Driver’s Wife, about South African white supremacist Eugène Terre’Blanche. Underneath it all, there’s a clear need from Broomfield to find an acceptance from his father of his work. They were frequently at odds with each other.

“I think he never had the sort of diehard firebrand politics of my mother, who was probably much more a fan of overtly political films. I think she was a much stronger supporter of my work.”

What Broomfield came to realise in the edit suite is how his father yearned to get away from his upbringing in Draycott. “The reality of growing up in a mill town… although it was a very beautiful place, it was a fairly tough upbringing, and I think they were pretty poor. They didn’t have enough money for coal, for heating. And so, I guess, my fascination for, in a sense, trying to understand what he’d come from, was something he knew all too much about.”

When we speak Broomfield is just putting the finishing touches to his next film — a follow-up to 2002’s Biggie & Tupac, which dealt with the murders of rappers the Notorious B.I.G. and Tupac Shakur. This latest work, he says, will be something of an exoneration for the late Russell Poole, the LAPD cop whose extensive investigations and theories were discredited. “He was proved to be completely right, which is great for his family and people who believed in him.” Broomfield fighting the good fight once again? His parents would be proud.

My Father and Me airs on BBC Two on March 20 and streams on BBC iPlayer