SYdney Devine and I have history.

Not a Culloden or Flodden war disaster - more a skirmish, you understand. But the fallout means it's a slightly trepidatious finger that pushes on the doorbell of his beachside bungalow in Ayr. Why? About 15 years ago, the aftermath of an interview with the singer turned out to be, well, less than devine.

The writing device - me taking on the position of Nuremburg-like prosecutor with the Cleland-born performer being held accountable for singing crimes against humanity - worked as well as a stringless guitar. Steak and Kidney, as he is known, certainly didn't blow tiny bubbles of delight on reading the result (And rightly so). And while interviews weren't exactly halted, he remained guarded.

But the episode has since prompted a few questions; how much of a sense of humour does Devine actually possess? Does the rhinestone catsuit cover up a canyon-sized ego? And will he open up to someone who has been rather unkind? Thankfully, the opening welcome is as warm as the tea his wife Shirley serves up with the Kit Kats. But let's begin with an easy question anyway. He's now celebrated his 40th anniversary at the Glasgow Pavilion with two sell-out shows; despite a previous retirement and a serious heart operation. But could the 74-year-old have imagined a career running almost as long as the Willie Nelson's hair?

"Never," he says emphatically, then breaking into a smile. "I remember selling out the Apollo in Glasgow for two nights and then moving to the Pavilion, which sold out within hours so we played for two weeks. And the success has continued."

It has, with sell-out shows and 43 million records sold. Does he ever wonder why? "Yes, it's because I never short-change the people who come to see me," he says in determined voice. "I once supported Charley Pride and on the night he ignored me completely, then ignored the audience and left without signing an autograph. That was a lesson in how not to behave." He adds: "I get women coming all the way from Toronto to see me play. There's no way I won't acknowledge that."

Ah, the women. Devine gives them his all on stage; a hip-­gyrating, brow-sweating display that has ladies of a certain age reaching for the menopause pills. But here's a trickier question; he clearly loves to perform, but how much does he need it? Devine thinks for a moment (recalling the war crimes adventure?) before answering. "Well, I never wanted success," he states. "Stardom was an accident. I was quite happy doing the working men's clubs in Sunderland or North Wales and all I ever wanted was to make a living as an entertainer, to feed my wife and kids. I never saw success on the horizon."

He takes a breath: "I once met Sheena Easton at Radio Clyde back in the seventies, when she had just appeared on Esther Rantzens' Little Big Time and Sheena told me she would ­definitely make it. No doubts whatsoever. Yet, I never once thought that. But did I need to be on a stage? Yes. And from a very early age. I sang in old folk's clubs as a 13-year-old for ten bob a go. And when I was up there, and I heard that round of applause at the end of the night, I simply loved it."

Was the younger Devine's contained ambition reflective of a lesser belief in his talent as a singer? Not a bit off it you discover, when he explains why he was upset to be once described as "Scotland's Daniel O'Donnell". "Here's why I was annoyed" he says, in sotto voce, with a twinkle in his eyes. "I can sing. I've got a voice that runs to three octaves."

Devine rates his own voice, then. Quite highly, it seems. "If I had my life to live over, I'd go to London, get a great vocal coach and do something completely different," he says. Opera? Musical theatre? "Who knows?"

Of course, fate deemed otherwise. He didn't so much grow up under a glass ceiling but a gas cloud. The son of a miner with a family of eight kids, Sydney and his three brothers would "fight for the school shirt". The youngster was lined up to work in a tailor's shop on leaving school but on the fated day absconded down showbiz avenue.

He joined the White Heather Club tour, as a whistler, programme seller and curtain puller. "The kids who do the X Factor just don't get this level of experience." But he didn't go down the tartan singing route because "there was too much competition" but also because the mid-fifties saw the doors of musical possibility blown wide open. On hearing Elvis, Devine headed for McCormick's Music Shop in Glasgow and bought a 14 guinea guitar on HP for "three quid down and a new address". He was soon billed as The Tartan Rocker and in fact came second in a competition to find The Scottish Tommy Steele (The soon-to-be sensational Alex Harvey won).

However, in the seventies, Devine switched track on discovering songs such as Maggie and Tiny Bubbles. His re-originations in upbeat tempo of three minute love-tragedy metaphors such as The Crystal Chandelier and Blackboard of My Heart sold millions. At one point he was making £30k a week.

But the music industry was (and is) shark-infested. Was he savaged? "Oh, yes," he says, ruefully. "One manager I had from Edinburgh took me for £70,000. But you just have to get on with it." He adds: "I tend to trust people. Shirley however can smell a bad egg a mile away."

That's not to say Devine is naive and sells himself cheap; if agreeing to a show, he'll work out the audience size and what a producer stands to make and match his fee accordingly. But what about the other predators out there? As a good-looking young performer, did he meet Saville-like creatures?

"Oh yes!" he says. "When I went to London to work with Ralph Reader, the producer of the Gang Show, he had all these good-looking young boys around him, and he was keen to 'look after me'. But thankfully my mother met him and realised what he was up to."

Sydney would later enjoy his own (hetero) sexual adventures. While on the club circuit he and Alex Harvey once shared the delights of nymphomaniac Scots twins. "There's a song lyric that says 'After all, I'm just a man. . .' he sings, grinning of younger years. "And of course the wally dugs (drugs) were also available. But I never touched them."

Devine is certainly opening up. So let's deal with the elephant in the room. How does he feel about the teasing in print, such as the war crimes disaster?

"Look, we all change," he says absolving me like a benevolent bishop would a mischievous novice priest. "And I don't mind constructive criticism. If someone has seen the show and didn't like it fair enough. But to have a go regardless?"

There's no paradox here: it's as clear as tiny bubbles Devine has a real sense of humour - yet takes himself very seriously. And he wants to grow his audience. As we talk about country stars who have played rock festivals, Devine admits he feels a little miffed at never being asked. Would he appear at T In The Park? "For sure!" he says, with the enthusiasm of the teenagers who populate the concerts. "I'd love to do it next year. And what a way to celebrate 75 years on the planet."

He also reveals he wants to show the world his oeuvre and record Nessun Dorma. And what's obvious is certainly loves to be loved. The singer could be spending most of the year in his villa near Mijas but is already making bookings for next year. However, the final question - how would he like to spend his (eventual) retirement - reinforces thoughts of the man. "I'd like to die on the Pavilion stage," he says, smiling, but entirely serious. "Why not? It would be the perfect way to go." Mmm. Stanley Baxter says he'd rather shuffle off on a sun lounger at his villa in Cyprus with a cool G&T in his hand. "Yes, that sounds nice, but I want to be with an audience," says Devine. "I want to hear that applause. There's nothing like it."

Sydney Devine will be back at the Pavilion Theatre, Glasgow, next year ("God willing," as he puts it).