GILBERT O’Sullivan puts the record straight straight away. Now, it was long assumed, since 1970 actually, when the singer-songwriter stunned us all with his Top of the Pops appearance, that his persona was dictated by a media-hungry management.

It had to be. No one in their right mind would choose to wear, especially in the age of androgyny and glitter, a pudden bowl hair coat, cut down trousers with one leg longer than the other, colliery boots - and the tragic stare of someone who had been recently institutionalised.

And no one in their right mind would choose such a stage name. He had to have been pressured into it, like his management stablemate Englebert Humperdinck. Ha! Not a bit of it.

“I must be the only artist whose image was hated by everybody,” says the artist born Raymond O’Sullivan, smiling at his Jersey home, his voice still bearing traces of Waterford.

“But I wanted to be different. In 1967, long hair was here to stay so I went instead for the Just William look, which came from a love of Chaplin and Buster Keaton.” He laughs; “Every single record company didn’t like it. (He went through several, with no single successes). I was always being told to wear jeans, look like James Taylor and I’d be okay. But I’m proud of the fact I decided to be different and look like a freak.”

There’s no doubt the image captured the attention, although in 1970 manager Gordon Mills signed the performer in spite of the image. But there was another reason for creating an alter ego; Shyness. Ray O’Sullivan could stay home while Gilbert dressed up (down) and took to Top of the Pops or perform concerts. “I’m basically as shy a person as I was when I once worked in an office in London in the late Sixties. I like my own company. I didn’t need a lot of friends.

“But there’s a dichotomy in my character. There’s also a healthy arrogance which emerges when I don’t need someone to say to me ‘I like your music.’ When it comes to my songs I’m confident. Back in 1967, I would go to a publisher’s office, and tell them they just had to listen to my music.”

He adds, smiling; “My motto is ‘You may not be as good as you think you are, but thinking you are is good.’”

O’Sullivan can sing on stage in front of a couple of thousand people and exude confidence. But if he were to meet any of those people afterwards the shyness would strike a discordant note.

What’s apparent however is that O’ Sullivan, with a new eponymously titled album out now, still has the determination he had in1970 on signing with Gordon Mills’ MAM label.

This perfect pairing created success followed by success. In 1972, O’Sullivan was the biggest-selling solo artist in the world, outstripping even Rod and Elton (the Bisto Kid image now dropped and replaced by long cardies). Alone Again (Naturally) sold two million copies in the US alone. But the “father and son” like relationship crashed however at the end of the Seventies when O’Sullivan queried his record deal, taking Mills to court - and coming out with £7m in back royalties.

Yet, it was a pyrrhic victory; Mills, who been a “father figure” and the pop star never spoke again. O’Sullivan was deeply hurt by events.

The songwriter has continued to write and perform however. But he won’t write anything but standard pop songs. “I’ve never been interested in writing a musical because I love the discipline of a three or four minute song. I’ve been doing it for nearly sixty years and the joy is to go into a room from nine to five and come up with something good or something unusual. It’s the Brill Building mentality.”

He adds in more serious voice; “The danger is we lose the melodic touch. We all love Paul Simon, for example, and his latest record sounds great instrumentally but it really lacks the melodic songs of his early albums. His integrity remains intact, as does that of Randy Newman, but the melody is all important to me.”

The songwriter’s more serious works such as Nothing Rhymed suggest a fair deal of existential angst? “I don’t know,” he says grinning of the theory. “I’m not into self-analysis . I just knuckle down and write the songs. And the songs aren’t always about me.”

O’Sullivan, who married Norwegian wife Aase in 1980, emerges as a simple bloke who’s incredibly focused on his work. Far from ever living the rock star life, he reveals he has now cut out the half a Penguin biscuit treat he once allowed himself each day. What? Come on Ray! Have you ever lost the plot? “I hope not,” he says, smiling. “My feet have been on the ground. I don’t drive, but I like a nice home. I’ve never been a red carpet person. I’ve never been someone to get carried away with those telling me how good I was or whatever.” He adds, “But I do have Norwegian chocolates and a glass of wine at the weekend.”

It’s not a huge surprise to learn he’s an obsessive compulsive. He has to straighten the rugs when he walks into a room. “I’ll get up, at 7am, my wife brings me breakfast, I’ll have a bath go down at 8.30 and then tidy the house before the housekeeper comes in.”

He pauses for a moment; “I think it comes from my mother. She told us the story of how she once went for an interview in London, and as she was leaving the room she noticed a bit of dirt on the floor and picked it up and carried it out. I think that helped her get the job. That’s something I think has been bred into me.”

He adds, grinning; “ I don’t have a hang up about OCD but it drives my wife and daughters crazy.”

O’Sullivan’s mother played a massive part in his life. After the family of six children emigrated from Waterford to Swindon, she bought the seven year-old music mad Raymond, a piano which was kept in the garden shed. She him to piano lessons in the hope he’d “at least be able to earn a bob or two playing in the local pub.”

And somehow a drum kit and a guitar appeared over the years, even though his dad had died when young Raymond was 12. “It’s sad I never really got to know him. What I do remember was he loved to gamble. If he’d lived until I was successful he’d have wanted me to buy him a racehorse.”

Having been Gilbert for so long, does his wife, for example, call him by that name? “Don’t be silly,” he says, smiling. “Everyone who knows me calls me Ray. But when people who don’t know me call me Gilbert that’s fine.”

Yet, Elton wouldn’t be happy to be Reg? And Sting doesn’t want to be Gordon. “Yes, but I’d have a problem calling him Sting.” He breaks into a laugh; “It’s the same with the U2’s The Edge. There’s no way I’m ever going to call him that.”

What’s undeniable is that O’Sullivan hasn’t been changed by money or fame. Even the busy hair remains, at 71. “I write pop songs,” he says, simpy. “I don’t see there’s anything wrong with that.”

But does he have no regrets on pop life so far? “Just one,” he admits, laughing. “I went too far in having pics taken in the short trousers. That was a big mistake.”

Gilbert O’Sullivan plays Glasgow’s Oran Mor on August 13 at 7pm.