Sometimes people look quite disappointed when they see me, having heard my name,” says Afua Hirsch wryly. “Because I’m not Jewish I have never really felt it’s an identity that I can own, but at the same time it’s an identity that follows me everywhere. I deal with it by wanting to find out about it. I’m almost like a shadow member of the Jewish community, always there asking questions.”

Asking questions is something Hirsch has made a career of, first as a barrister and latterly as a journalist for the Guardian and Sky. In her new book, Brit(ish), Hirsch — whose maternal grandparents came to Britain from Ghana, and whose Jewish paternal grandfather escaped Berlin and the Nazis in 1938, before marrying an English woman — asks plenty more about identity, immigration and what it means to be mixed race and mixed heritage in modern Britain.

The book combines personal stories — the teenage, privately educated, middle class Hirsch being refused entry to a Wimbledon boutique because “black girls are thieves” — with analysis of Britain’s attitude towards race. Hirsch covers everything from finding hairdressers who could manage her hair, to pronunciation; in Ghana she is scolded for speaking Twi in an English way — “you have to be rough, dismissive and direct” — something that will resonate with anyone who has heard polite attempts at Yiddish.

Hirsch examines why her grandfather Hans — who swiftly became John and settled in Kent — was seen as the “good immigrant”, unlike her mother’s parents. Largely, she concludes, it was down to skin colour. For although there were “objective things that made Jewish refugees desirable, in terms of the level of education and qualification they brought”, her mother’s father was Cambridge-educated, settling in Britain in the 1960s after working in the upper echelons of Ghanaian politics.

“There is the thing about visible difference; it was easier for [Hans] and his family to blend in without presenting that constant visual reminder of their otherness,” she says. “It’s that first question, ‘where are you from?’ — you never get the option of just blending in.”

Hirsch highlights how British people are comfortable talking about some aspects of the past — such as the Second World War — but less so about the legacy of slavery and colonialism, other than in the context of abolition.

With the war, she says, “it’s quite clear which moral side of the argument we were on”, even if the full picture — including Britain’s reaction to the Jewish refugees — is more complex. “It doesn’t create any dilemmas for Britain’s sense of self,” she says. “Empire and slavery is the reverse because in hindsight I think everybody in Britain would agree Britain was on the wrong side of history.”

The challenge, she argues, is in accepting that our history can include moral abhorrence. “I don’t think that obscures the ability to celebrate your country. The thing I value most about Britain is a sense of intellectual curiosity. I can’t understand why in 2018 we’re still so unable to do that.”

Brit(ish) is Hirsch’s record of her search for her identity — “it’s a book the younger me would have liked to have read” — including a period spent living in Ghana. She knew grew up knowing less about her Jewish ancestry, and wishes she had asked John more before he died. “The way my grandfather dealt with his experience was to bury it, so my father didn’t know his father was Jewish until he was a teenager,” she explains. “My awareness [of my Jewish heritage] has always come from external sources, from other people asking me about my name. I don’t think I had a remotely good grasp of it until I started studying the Second World War.”

John grew up secular in Berlin and divested himself of his Jewishness after arriving here. “I don’t think he had a space with which to cope with the trauma. I wonder if he’d been part of a community where other people shared that experience he’d have had the space to deal with it, but he was living in homogenous Kent in the 1950s.”

In later life, he opened up more; Hirsch relates to Philippe Sands’ East West Street and the fact of grandchildren being the ones to pry open those memories. “Having grandchildren who felt it was part of our story made him see it from a different perspective.” Her great-uncle, now in his 90s, has started speaking about his experiences too, spurred on by the refugee crisis and his feelings about Britain’s responsibilities.

Hirsch wants to start a discussion around identity in Britain, a conversation she thinks Jews are already further ahead on than most. “Often they have something to say and they’ve thought about it — I really relate to that,” she says.

She thinks “whiteness” is poorly understood here. “Most people think to be white is to be normal and everything else is a minority identity,” she suggests. “They might understand a little bit about, say, how Jewish identities were constructed or how black identities have been constructed over time, but they don’t know that ‘whiteness’ is constructed — it doesn’t exist in biological fact any more than any other ethnicity.”

The book notes the often negative reaction to BME (Black and Minority Ethnic) networks being set up in offices. “I think people feel threatened by the sight of black people especially congregating together,” she says. “I’ve noticed in workplaces this thing of people subconsciously trying to blend in. One thing that goes against it is being seen with other black people.”

Hirsch is not overly optimistic; we are not living in any kind of post-racial society, and she mourns that Britain has never had a moment like the civil rights movement in America “when we have looked at our identity and our structural inequalities and how they affect different minority groups”.

“We’ve lost the overt racism that people described in the 50s or 60s, which is obviously positive,” she says. But she worries modern racism is harder to combat because people deny its existence, and because discussion is often couched in terms of diversity. “We’ve moved away from naming the problem, we’ve got all these comfortable labels,” she says, adding that corporations are using phrases like diversity rather than really grappling with the issues.

At the same time, prejudice has partly been transferred elsewhere, including towards newer immigrants and Muslims. Hirsch describes going on an English Defence League rally as a journalist, and being told, “you’re OK; it’s just the Muslims”.

“It was sobering,” she recalls, adding that “overt prejudice” towards Muslims is expressed in public spaces in ways that no one would find acceptable about black people or Jews. “There’s so much ignorance.”

Writing the book has clearly been cathartic for Hirsch, who examines her struggle to fit in in Ghana as well as in Britain. She has been to Berlin multiple times, to where her grandfather lived, and the family is trying to establish where their great-grandfather was buried. “I hope next time to go I will have more information.”

She hopes Jewish readers will read and debate her book. “Even though I’ve written mainly from the experience of having African heritage, I’ve partly written about my Jewish heritage and I think it’s a story other people will relate to.”

Ultimately, her aim is to make people think about race and identity. “We’re too willing to have the same conversations,” she sighs. She wants to go beyond superficial debates, and empower people to really ask questions, without fear of saying the wrong thing.

“There are definitely well-meaning people who want to engage more but are handicapped by the difficulty around language,” she says. “That’s not in anyone’s interest. It shouldn’t be a taboo.”

‘Brit(ish)’ is published by Jonathan Cape on February 1. Afua Hirsch will be speaking at Jewish Book Week on March 7.