A MIDDLE aged man strolls across Royal Exchange Square in Glasgow’s city centre with ripped jeans that are at least 20 years too young for him, a spiky haircut borrowed from the 1980s, black slip-on shoes and no socks.

He gets a few glances, not too many, it’s just a bit early for that, but had this been a few hours later then it is unlikely his journey would have been so uneventful.

Maurice John Giblin Johnston, for it is he, is back in town for a few days and will take in Sunday’s Old Firm Scottish Cup semi-final at Hampden as a pundit for Sky. It is fair to assume he won’t be walking to the game, although those who suggest he would need an armoured vehicle go too far.

But in saying that, emotions remain raw among the Celtic fans when it comes to Super Mo. He had been one of them. He left for France where he went from being a good to a great player. Billy McNeill thought he pulled off a coup by getting a someone who by then was one of Europe’s best strikers, but no contract was signed, Graeme Souness with the help of agent Bill McMurdo pounced, and the rest is history.

There is footage floating around of Rangers fans being interviewed at the time who made it clear that “their club was for Protestants” and then for comic affect added that when it came to Catholics they had “nothing against them.” But Rangers had changed, and for the better, even if it took longer for some to be dragged from the middle ages.

“There was only one time I felt threatened,” recalled Johnston during a long and fascinating chat. “I went to a Rangers Player of the Year supporters’ night in Larkhall; the people at Rangers told me I shouldn’t go. But I told them I had to go because it was my first Player of the Year, so I decided to go, but it was a bit rocky to say the least.

"By that I mean I felt uneasy. No-one made me feel uneasy but with what everybody was saying to me, I had that feeling in the back of my head.

“Te award I was given was Best Newcomer. It was a made-up award. I think three of us went and Ian Ferguson got the main award but I was a bit late walking in and it was, interesting.

“Did I sing any of the songs? I did actually and it ended up on the front page of the Daily Record – I had to sing! But look, it was like everything else, I felt scoring goals and working hard for them would win them over.”

Winning over the Rangers fans actually proved far simpler compared to dealing with the reaction of his former colleagues who, and it’s astonishing to think of it now, had Johnston as a guest on their team bus as they made their way to Hampden for an Old Firm Scottish Cup Final in 1989.

“The one reaction that really got to me was Tommy Burns,” admitted Johnston and you could tell it still did. “I was very close with Tommy and he was like ‘ya wee runt,’ and all I could say to him was: ‘hey, sorry Tommy.’

“But he told me his kids has been singing ‘Mo, Mo, Super Mo,’ at the breakfast table on the day they thought I’d signed for Celtic. That made me feel really bad. He got his head round it eventually.

“We were really close, Tommy and I. He’d come to my engagement party, singing songs, and he was everything Celtic was about. But years later I looked after his boy, Jonathan, when he came over to Toronto to do some coaching and showed him around the club.”

Johnston went from hero to persona non grata at Celtic, the team he supported. Did that ever bother him?

“No. You support whatever club you play for,” he said. “As soon as you pull the jersey on it’s like everything else, you want to win. Nobody walks out on the park to lose or to make themselves look stupid.

"The day I put that Rangers jersey on I had to make sure I was making myself number one in the team every single day. Every day at training I had to make sure that, walking into that dressing room, I had the support at my back. Because if I don’t have that I’m nothing.’

Any regrets?

“No. None at all. In my whole career I always liked moving and seeing different cities and going to different places. I was in London, Miami, New York, and Toronto. Football took me to places I only ever dreamed of. I got bored easily.”

Johnston now lives in Florida and he isn’t come back home. Not next year, not ever. American life has treated his family well and, let’s face it, living in the west of Scotland for a man known to thousands as Judas is not going to enjoy a quiet life.

Even now he is seen as the traitor who jumped the dyke; however, the Celtic board at the time hardly covered themselves in glory.

“Look, at the end of the day Celtic didn’t have the money for it,” said Johnston. “That is the bottom line. There was a transfer fee, plus everything else that was involved, I hadn’t signed and then all of a sudden Rangers came in.

“If I had signed a contract, I would have been with Celtic. That would have been it. The contract is there, it is away to FIFA having been signed; it wasn’t signed. Money came into it. I make no bones about it. I am not going to hide from any of the facts."

Johnston went into hiding in the weeks after he was paraded at Celtic Park wearing a truly awful jumper until next we knew he was pictured standing on the Ibrox pitch with a red, white and blue scarf over his head.

“I feel pride in the sense of what I achieved at both clubs," he says now. “I could have gone to Rangers and failed, having put myself in there. But I knew I had to run faster and harder than Ally McCoist, Mark Hateley and whoever else I was playing with. I knew deep down I had to win the Rangers fans over.

“But in Glasgow winning people over is about working hard. So that was my first objective, to work hard.”

Johnston laughs as he revealed Murdo MacLeod had recently asked him whether he going to the dinner at Celtic Park which will commemorate 30 years after their team stole the league from Hearts. Sadly, he will be a no-show.

Sons TJ and Tyler, 15-year-old twins who by all accounts are good footballers in their own right, recently discovered what happened to their dad that day at Love Street when he scored one of the finest goals – perhaps even the finest – in Celtic history.

“For me it was an unbelievable goal, it was surreal,” said Johnston. “It came from Danny McGrain, into Paul McStay and then a Brian McClair nutmeg, the whole lot all the way down and then a tap-in.”

There are three Celtic legends named there and one Judas. It was that way in 1989, it is now and will be 30 years from now, and Mo Johnston is quite content about the life he has led and decisions he made.

But he needs to wear socks and cut his hair. He’s in his fifties for goodness sake.

Sky Sports will show the Scottish Cup semi-final between Rangers and Celtic this Sunday, and from next season every Old Firm derby in the SPFL, exclusively live.