SO, are you middle class or working class?

How can you really tell? Here’s a tip. “If you want to know if you live in a working-class area, walk around the corner and see if there is a Greggs and two bookies and a chippy,” Darren McGarvey suggested on Radio Scotland last weekend. “I don’t care how much your mortgage is, you’re living in a working-class area.”

McGarvey was Edi Stark’s latest interviewee on the new series of Stark Talk and what a sparky encounter it proved; funny, challenging at times (for both interviewee and interviewer), at times even feisty. In other words, great radio.

McGarvey is the Orwell Prize-winning author, rapper and, as he has never hidden away from, former addict, who is that still all-too-rare voice in the media landscape, a working-class commentator.

Stark, one of Radio Scotland's crown jewels, was interested in getting to the root of who he is by talking about his roots, growing up with a mother who herself was an addict and who, at times, threatened her son with violence.

“Her behaviour was dangerously unpredictable,” Stark suggested, citing McGarvey’s own account in his book Poverty Safari. “I guess it was,” McGarvey replied.

But when she tried to dig into why that might be he was reluctant to go there. “I have got to have boundaries in terms of what is safe for me to discuss,” he told her. “And also, having already discussed things at a certain level of depth in the book, that doesn’t then mean that I have to recount it every time I’m asked.”

Stark wasn’t so sure. “But you do when it’s a biographical interview about you and it’s very important.”

“Well, no, I don’t actually.” he replied. “Other people might think they do. They might have that reverence for journalists. They might think that they have to perform for the media, but I don’t.”

As someone who also asks people questions about their lives for a living, this was thrilling. But I think it would be to anyone listening. Stark pushing, McGarvey pushing back. “My story is not just my story,” McGarvey pointed out.

It should be said there was no needle in any of this. Having spent time in McGarvey’s company I can vouch for the fact that he is entertaining company, as Edi Stark found here. And more than capable of being self-reflective.

When she asked him if his relationship with his mother might have affected his subsequent relations with other women he admitted, “I just wanted to be in love. I just thought having a girlfriend was going to fix me.”

This was, as Stark pointed out, a biographical interview and so dealt with his traumatic upbringing, his addiction, his relationships, but if there was a frustration it came from the fact that what he writes about wasn’t delved into more. McGarvey is a voice that we don’t hear enough. How many others who contribute to Britain’s op-ed pages live around the corner from Greggs? Not many, I suspect.

At one point Stark asked McGarvey if he worried about retaining his authenticity as his material circumstances changed. It’s a question that he has wrestled with himself in the past. Listening in, though, I did wonder when was the last time anyone asked Polly Toynbee or Daniel Finkelstein, say, if they are still “authentically middle class”.

McGarvey always has to prove his credentials in a way that they don’t.

Still, this was a bracing, vibrant half-hour. “God, I feel like I’ve been in the gym,” McGarvey said at the end, laughing.

Listen Out For: Property of the BBC, Radio 4, Monday to Friday, 1.45pm

In a new series Robert Seatter, head of history at the BBC, chooses 15 objects from the broadcaster’s archive to show the changing history of the organisation.