For anyone who takes literally the maxim about not having been around in the Sixties if you can remember the period, Marianne Faithfull must have been very absent indeed. She recalls that glorious and disastrous time in minute detail, right from the day she was found and made famous as a 17-year-old by the Rolling Stones manager Andrew Oldham; all through her public and passionate romance with Mick Jagger, and the notorious drugs bust at Keith Richards’s Sussex farmhouse when she was said to be in – how to put this delicately – intimate possession of a Mars bar.

It is the very stuff of pop folklore, with its origins in an England that from this distance looks both naive in its decadence and slightly fearful in its defiance of the old order’s authoritarianism. In the intervening time, Faithfull has matured from the original rock chic, via toxic diva, to her present and improbable role as a genuine English chanteuse. It is this journey, during which she all but died, that makes her such a rich study for The South Bank Show on Sunday.

Today she is to be found with her younger French lover François in a Parisian apartment. The setting could almost be an answer to the relentless question of that Peter Sarstedt song, Where Do You Go To My Lovely? It is in a posh embassy street, bang next door to the British Consulate, the very kind of place from which British teenagers would sheepishly seek help if they’d screwed up on the Continent.

She is triumphantly blowsy, with marbled underarms and hair as blonde as the day she recorded the Jagger/Richards number As Tears Go By more than 40 years ago. She is 60, a grandmother, and, as if to flaunt the comic cycle of rebellion and conformity, she says proudly that her son Nick is a very successful financial journalist.

She is also knackered and broke, these last two adjectives being her own. She wonders if the tiredness is down to her liver, which took a terrible hammering during her long years as a heroin addict and hard drinker. “Worked too hard and played too hard,” she says with a seriously weary smile. “Oh, of course I should have made money. But the time when I should have been working was when I was on drugs and living on that wall in Soho. But then only a few people make a lot of money in this business. I’m trying to put aside as much as I can. I think we’re going to have to find somewhere a little smaller and cheaper to live in than this.”

She has just returned from appearing at the Festival des Mots in Toulouse and has three more dates left on her current European tour. She says it’s probably all this travelling for work that has also exhausted her, and that she would now like to spend more time in the recording studio. She’s turned into a really solid lyricist of the broadly European school, lived-in and philosophical, looking back, but not too hard. Sentimentalism is kept at arm’s length with sudden barbed lines of franc-parler, such as “When we are old and full of cancer . . .” Some of them sound raddled, as much spoken as sung, testimonies of survival, with a Piafian distaste for regret. Billie Holiday and Bessie Smith are two of her absolute heroines. “I wanted to change history,” she says. But what does she mean by this? “I mean that I didn’t want [my life] to end up in the way it was going to.” Because of drugs? “Yes.”

She was the real thing, living rough in Soho, a registered addict, spurning offers of help and money from her rich friends from the previous decade, in particular Jagger and Richards. “They tried to keep in touch,” she says, “but I couldn’t respond. I couldn’t manage that whole way of life. It wasn’t for me. I got into the whole thing by accident. I was just this girl from Reading.”

But what a girl. The things she is saying are made more poignant by a framed collage of newspaper cuttings on the wall behind her. There are the headlines about Jagger being arrested for possession of cannabis; the girl at the party (Marianne) wrapped in nothing but a fur coat. The woman now old enough to be that girl’s grandmother still has the perfect bow of a mouth with its involuntarily seductive smile. “But, you know, I still don’t know what impression I was giving. I led a very quiet life. I didn’t really understand.”

She sounds as if she is fishing. I can’t quite believe that Marianne Faithfull is asking me to explain the allure of her youthful looks, but when I try, she doesn’t stop me. The point was, she was sexy without seeming to know it, which only made her sexier. She looked virginal even if she didn’t behave that way. She was a convent girl. Her parents were a bit exotic – father a former spy, mother a declassée baroness from the Habsburg dynasty.

I’d been led to believe that she would never again talk about Jagger, the Mars bar and prostitution. Quite the reverse. The first of these was, and remains, very real. He was, indeed, the one, although they were bound to come apart; the second and third are pure fabrications. “I don’t know where they [the Mars bar rumours] came from. I really should have been able to shrug them off after all this time, but for some reason I can’t.” The same, she says, with notions that she had gone on the game to feed her heroin habit. “I had friends who did,” she says, “but one of the reasons why I never needed to even think about doing that was because I kept going back to my mother in Reading and asking for money. Which I’m quite ashamed enough of.”

As for Jagger, he recently reappeared in her life, albeit briefly. That song lyric about being old and full of cancer was a lived line. Late last year she underwent surgery to remove a lump in her breast. She says she was lucky; but she was also vigilant and it was caught early enough for her to need no radiation or chemotherapy.

“Mick managed to track down my number at the hospital and called up to see how I was. It was really good to hear from him.” Have they stayed in touch since? “No. The thing is, people come together for a certain time in their lives, and then their paths go in different directions and you don’t see much of them. But they are still a part of your life.” Would it have been different if they had had their baby (she miscarried late in the pregnancy)? “I don’t know. I’m not an if-only sort of person.”

Did she mind when he married Bianca? “Yes, I did.” And Jerry Hall? “I minded that too.” And when he got together with L’Wren Scott? A pause. “Oh, he can do whatever he likes.”

As can she. She’s even choosing to stay away from The South Bank Show party for the programme about her. This is not a cool snub in the Kate Moss manner, but more of that weariness. It’s London, she says. She can’t be doing with it and what it represents for her. She likes being out of it, in a way that is a world removed from the other meaning of that lethal phrase.

*The South Bank Show is on ITV1 on Sunday at 10.45pm

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