IF Scottish football is a large, gaudy clockwork toy, then there is a growing belief that Chris Sutton is standing behind it holding a key.

The Englishman, after all, has been decried as the ultimate wind-up merchant. There is ample evidence for this assertion in the pundit’s past but there is also a convincing explanation given by the former Celtic player for his frankness on BT Sport or in his newspaper column in the Daily Record. He is, again frankly, unmissable on both but those who denigrate him as a pantomime villain are missing the bigger picture or even the sub-text.

Yes, Sutton is a wind-up merchant. He chuckles as I remind him of his propensity to unsettle his fellow professionals, whether at Celtic or Blackburn Rovers. He denies reports that he would strain the frazzled nerves of Martin O’Neill before Old Firm matches with verbal grenades gently rolled towards the manager, but he does admit he sought to unsettle John Roberston, Celtic assistant manager.

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“You can imagine the dressing-room before a Rangers match,” he says. “There were nerves everywhere. I would just mutter to John: ‘I have got a bad feeling about this one. I think we will get thumped’. He would go ballistic but eventually I did it so often that he would look at it as a lucky charm and get annoyed with me if I did not say it. So I didn’t.”

He was similarly perverse with team-mates. Graeme Le Saux tells of how Sutton drove home from training at Blackburn to the full-back’s cottage in the Lancashire countryside. Sutton once had his children in the back and Le Saux asked the striker if he and the kids would like to come in for some lemonade as the car pulled up outside the small but beautiful cottage. “Naw,” replied Sutton. “I don’t allow my kids to go into homes worth less than £250,000.”

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Le Saux said that Sutton only changed gear, not expression, and pulled away from the roadside with no indication of whether he was joking. “Did he say that?” says Sutton, again with a chuckle. “I can tell you I wasn’t being serious. But that is my humour.”

This ability to prod and provoke has not left him as a pundit but there is a substance to Sutton as a commentator, in print or on screen, that goes beyond any childish attempt to irritate. There are genuine, revealing reasons behind the 43-year-old’s committed presence.

The season has barely lasted long enough to scuff the first goalmouth but Sutton has already severely criticised Craig Gordon, verbally demolished Saidy Janko, both of Celtic, described the Rangers central defence as hopeless and Joey Barton as under-performing, while almost incidentally calling referee Craig Thomson a "bottler", leading to a series of controversies that have led to talks between the SFA and the broadcaster.

Sutton says there are both business and personal reasons for his bluntness. “This has nothing to do with pre-agreed script. This isn’t an act,” he says. “I do not come into a game with anything pre-conceived. I have learned a lot from the people I am lucky to work with. At BT, they are determined to put out great shows. My view that I can help them do that by being as honest as I can be and say what people are thinking at home.

“I watch a lot of TV and I find some of it extremely tedious and boring because people don’t want to say the things they should be saying. I am not always right, and if I am not right I soon know about it, but I think it is important to have an opinion.”

He adds: “I get in the line of fire over being critical of Janko, [Ronny] Deila and Craig Gordon. But I will be judged on my opinions and that’s okay. I won’t sit at a match at Rangers against Hamilton at the beginning of the season and give a Rangers player man of the match when it was simply undeserved.” It may be worth adding that Barton was named man of the match in this fixture, screened by Sky.

“I engage with the criticism on social media, or the more reasonable elements of it, because I know the passion for the game in Scotland. But I can’t worry about what fans think about me because my duty is to my employers,” he adds.

But what of his victims, does he ever regret the harshness of his tone or his words?

“I was lucky in my career because it was not all plain sailing,” he says. “I failed badly at Chelsea. I went there for big money and I became a laughing stock in England. I can offer good insight on triumph and disaster because I have experienced it.”

After stellar spells at Norwich and Blackburn Rovers, where he won the English title, Sutton signed for Chelsea for £10m in 1999. But after one season he was offloaded to Celtic for £6m.

“When I came off the pitch, I knew when I was good, but I knew when I was bad. I didn’t need a commentator or a reporter to tell me. I liked the adulation but I understood why I got panned at Chelsea and I have no complaints about that.

“The bad experience at Chelsea worked to my advantage. Football had been great for me at Norwich and at Blackburn and I probably took it for granted. But after Chelsea every day I got up and went to training and I relished it. There were big, big characters at Celtic – [Neil] Lennon, [Henrik] Larsson, [John] Hartson, [Stiliyan] Petrov. You had to be sharp on your feet to survive. That has probably helped me on TV.”

But do any of his targets of criticism ever challenge him? “Well, not yet,” he says. “I would not be frightened to say what I said on TV to somebody’s face. Some things have to be said. You can’t kid the football fan. For example, you can’t say Janko had a good game against Hapoel away and retain credibility.”

He also has verbal jousts with former players Stephen Craigan and Michael Stewart, his fellow BT pundits. Craigan, in particular, can be mercilessly addressed. “Myself, Stephen and Michael do not always see eye to eye. That isn’t an act. We do not sit down beforehand and I say: ‘I am going to say this so you should say that’. It is just that I am right most of the time and they are wrong.”

The last is said with a Sutton smile but it does not detract from his seriousness. “You make your argument on what you see and you are there to be shot at. I like that. Everybody is entitled to their opinion but I can give an insight into what players are thinking during matches. The beauty of having played in big games is that you can give the viewer or reader an insight into that experience.”

The Sutton cv is impressive. He was part of a Norwich City team that put Bayern Munich out of European competition, a Blackburn side that lifted the English title and a Celtic squad that won four titles, three Scottish Cups, a league cup and reached a UEFA Cup final. He went on to manage Lincoln City for a year but seems now to have focused on punditry. “You can’t say you never would,” he says of a return to management. "But I wake up in the morning and I am genuinely excited by what I do and by the people that I work alongside.”

He is also a passionate advocate of Scottish football. “Celtic getting to the group stage of the Champions League meant people in England are talking about the game in Scotland. I live in England and I bang the drum for Scottish football. I am a huge fan of Scottish football and it was good for me.”

So what of this week’s match when his old club takes on Rangers? Sutton will not be on broadcast duty but has, of course, his opinions.

“It is absolutely crucial after last season’s Scottish Cup semi-final when Rangers played Celtic off the park. Brendan Rodgers is a breath of fresh air. He has recruited well and I think Celtic are moving significantly ahead of Rangers.

“Mark Warburton has a problem and that is the expectation level. Many Rangers fans won’t accept second place but the reality is that Rangers have just come up and to get anywhere near Celtic this season would be progress. That is my view.”

There is no chuckle. No intimation of any winding-up. There can be no doubt about the sincerity of the opinion. After all, John Robertson is not within hearing distance.