Have I just offended Barbara Dickson? As she looks at me intently and, to put it mildly, goes off on one, I am beginning to think it’s a possibility.

To be honest I thought it was a mild enough question. Why, I’ve just asked her, now that she’s on the verge of her eighth decade on this planet, does she still want to get up on stage and sing?

“If I were a fine artist …” she starts, before stopping and then turning it around and asking me a question. “Would you have the temerity to say to John Byrne: ‘John, why don’t you just have a cup of tea and not do this anymore?’ Well, you wouldn’t do that, would you?”

I don’t get the chance to answer. She’s on a roll. “But because I’ve been in showbusiness people say to me: ‘Well, obviously, you’ll have to retire.’”

“Why? Why would I stop? Unless I’m rubbish. If I’m rubbish come up and say. That will stop me. There’s a lot of people who should have stopped long since.

“I might be arrogant but I still think I sound really good. I’m not doing it for the money. I’ve never done it for the money. I think what I’m doing has got worth.

I go to say something, but she still has the floor. “I know people think of me as West End Wendy, an ex-pop star. Well, that’s nothing to do with me. That’s a string to my bow which is 30, 40 years ago. I’ve had other successes too, but people take a photograph when they first notice you, whether it’s on Top of the Pops or The Two Ronnies or it’s in a concert in 1981 and in their indexing system that photograph comes up when the name is mentioned.

“They think: ‘Big hair, shoulder pads.’ Well, if they think that they don’t know anything about me because they haven’t shown an interest. Don’t say that’s what I am because it’s not.”

Today, Barbara Dickson has her hair piled up but she’s not big-haired. Her shoulders are conspicuously unpadded. She looks older than her 1981 vintage but not old (her 70th birthday is in the autumn). She’s wearing golden shoes and, right at this moment, a sense of righteous indignation.

It rather suits her. And in truth all this passion, I suspect, is much more Barbara Dickson than the big hair and the shoulder pads ever were.

It is January in Edinburgh and we are sitting in the Balmoral Hotel on Princes Street. Some 50 years ago Dickson moved from her native Fife to the capital to work in the Registrar’s General office just across the road from where we are sitting just now.

In the summer of 2015, after decades living down south and with her three sons grown up and moved out, she finally packed up her house in Lincolnshire and her English husband Oliver and came back north to live in Edinburgh once more.

Is it the same country she left in the 1970s? “Sometimes it’s not as nice as it was then. There was much more of what I call the right kind of camaraderie then. We were very proactive about our own communities. Our feeling of belonging was very strong. I’m not certain it’s as real now.

“People are belonging to a place that I don’t think exists. There is a kind of ‘Brand Scotland’ which I don’t like very much. I don’t think we need to have Gaelic signs in Edinburgh. We’ve never spoken Gaelic in Edinburgh. This is not ‘Brand Scotland’ here. The Scots language – my language – doesn’t get a look in.

“It’s great, it’s sexy, that language. It’s very sexy. Humour and sex are what I associate with the Scots language. I’m talking of the songs of Fife and the Lothians and the east coast. We are different here. I think I might break away,” she laughs. “UDI for the east coast.”

Spend any time in her company and it’s quickly clear Dickson is not – was never – a West End Wendy. She is very proud of her Fifer roots. Born in 1947 in Dunfermline, she grew up surrounded by miners and communists. “I was never a card-carrying communist. I have never been a member of a political party in my life. But I know where my sympathies lay and throughout my life I’ve never changed.”

As a teenager in the 1960s Dickson began to play in folk clubs in Dunfermline and St Andrews. She was a contemporary of Billy Connolly and Gerry Rafferty and loved the camaraderie of that. She was possibly the only solo woman on the circuit. “I was just with a load of blokes most of the time and blokes are great.”

She describes what followed as a series of lucky accidents. She met the Liverpudlian playwright (and huge folk fan) Willy Russell who thought she would be perfect in his play John, Paul, George, Ringo and Bert. It was a huge success and then Robert Stigwood then invited her to join his record label.

Soon enough she was having hits (among them Answer Me and Another Suitcase in Another Hall from Evita), culminating in the huge success of her duet with Elaine Paige, I Knew Him So Well, and turning up as a guest on The Two Ronnies TV show. The big hair and the shoulder pads years.

The 1980s also saw her take the lead role in Willy Russell’s huge West End success Blood Brothers, for which she won an Olivier award.

That’s the CV of a successful artist. But speak to her now and her take on those years is a little more complicated. She describes an artist who often struggled to find a niche.

“Record companies never knew what to do with me. I did write but I was not really a writer. I was never a sex symbol either. People didn’t look at me and go:’Phwooar. Let’s get her in a bikini and give her pop music to sing.’ I was extraordinarily different, I suppose, for a pop star.

“There was the tendency to cast me as the girl next door, which I am not and never have been.”

At times she wasn’t any surer of what or who she should be than the music industry either. “I haven’t always known what I wanted. But I’ve always know what I didn’t want. I don’t want to be a figure of fun.”

Even so, she admits, she was bullied into certain things by her then management. Plus, she struggled with the very idea of success. “Well, I went completely bonkers about three times. I went completely bonkers in Blood Brothers and I had to be carried out feet first because I couldn’t cope with being in the theatre six days a week being somebody I wasn’t and not being able to escape from it and having to be brilliant every night of the week. That is enough to drive anyone around the twist. And indeed it happened.”

Did Dickson feel she had agency back then? “I always said what I felt. My late lamented darling friend Gerry Rafferty was afraid of ‘the man’. He didn’t like ‘the man’. So he kind of shot himself in the foot all over the place because he didn’t want to risk being fecked over.

“However, if you’re going to be in it you’ve got to be in it to win it to an extent. You’ve kind of got to go with the flow. Gerry never learned to do that and I kind of went with it.”

The lasting legacy of those years at least, she says, is that everybody knows who she is. Her friend Charlie Dore, a singer-songwriter she adores, struggles to get bookings to play live because people don’t remember the name. Dickson never has that problem.

The danger is they expect her to be the girl from 1981. And that’s not who she is. In the 1990s she retreated from the West End Wendy era and returned musically to her roots. These days you’ll find her singing murder ballads, Tom Waits songs, and those “sexy” Scots songs she loves so much.

And she’s not going to stop just because she turns 70 this autumn.

“I want to continue doing what I do now. I’ve got Olivier awards. I’ve got platinum albums. I don’t need that. I don’t want prizes anymore. I just want to be a sort of elder stateswoman of music in the field that I know about.”

What does that mean? It means Barbara Dickson has come home. In every sense.

Barbara Dickson plays the Carnegie Hall, Dunfermline on February 26, Queen’s Hall; Edinburgh on February 27; Concert Hall, Perth on February 28; and the Royal Concert Hall, Glasgow on March 1.