LOU MACARI’S first inclination was to switch off his mobile phone when Manchester United drew Celtic in this season’s Champions League. “I had just become the most wanted man in two countries, ticket-wise,” he says, laughing.

Macari has split loyalties. United and Celtic were his only two clubs as a goalscoring midfielder in the 1970s and he hopes both can progress, but already doubts that will happen: “The first two results in the group being draws make the games between Celtic and Manchester United even more important and one of the two may miss out.” He doesn’t say as much, but that is unlikely to be United.

The gulf between European champions and leaders of the Scottish Premier League should be too wide for Celtic to bridge, though Macari believes both games could be close. In the 41 years since Celtic became the first British club to lift the European Cup, the expectations of the Glasgow supporters have faded little. Macari feels the high hopes of the Celtic crowd were partly to blame for the goalless draw against Aalborg, the group’s perceived Danish whipping boys, in the first group match but believes things will be different on Tuesday.

“They expected a cricket score and got frustrated,” said Macari. “Nobody will anticipate that against United and, because they’d take a winning goal in the 89th minute, the fans will be more patient. In that respect, the pressure’s off and the two games could be a lot tighter than people think. Anyone is kidding themselves, though, if they think the standard of player has improved at Celtic. Aiden McGeady [Celtic’s current crowd favourite] would just have been a squad player 30 years ago.”

Strong opinions are Macari’s vocation these days as a media pundit, predominantly for MUTV, though he quips that he tempers them sometimes if he thinks Sir Alex Ferguson might become an angry viewer.

Macari joined Celtic aged 18 in 1967, leaving six years later, having refused a new contract offer. His manager, Jock Stein, thought Macari would join Liverpool. He signed for United. First he had rejected Stein, then Bill Shankly. He should have got a medal for bravery.

Macari has deep affection for Celtic and for a while he also had deep regrets. It was the club he always wanted to manage but even when given the role he had little chance. He was bitter for years after being sacked by new owner Fergus McCann in 1994 nine months into the job. Then the real world kicked in and football ceased to matter.

On Wednesday, April 28, 1999, Macari’s 19-year-old son, Jonathan, was found hanging from a tree in Stoke-on-Trent. Jonathan had signed for Nottingham Forest in his youth but was released at his own choosing. He took his life less than a year later. Before Macari was told the news, he sensed what it would be when the police contacted him. “From that moment to almost a month later, I think it’s fair to say that everything more or less went blank,” says Macari. “I went home to where my wife and two other sons had gathered. I can remember us all being sat there looking at each other for hours. There’s nothing to say. It’s numbing. You ask yourself what could you have done? The role of football changed in my life at that point. It became irrelevant.”

In his recently released autobiography, Macari blames himself for the loss of his youngest son. “I looked after some terrific kids at the clubs I’ve been at and if they were unhappy I’d always find out why. When I lost my own lad it occurred to me that I hadn’t done the same with him. I didn’t sit down and guide him in the way I should have done. I made a big mistake both in not being there for him and not being tough enough on him.”

When his family read the first draft of his book, they questioned Macari’s conclusions. “They didn’t like me saying my son got too much money, but I maintain he did. He got £5,000 just for signing a contract at Forest and a loyalty bonus of £7,500 after 12 months. Money in a young man’s pocket is a recipe for disaster and we had that disaster. Only when you go through that do you understand the hell of it.”

When Macari looks at football now, it is from this perspective. For all the game has given him, including 42 Scotland caps, an FA Cup winners’ medal with United and managerial posts at Swindon, Birmingham, West Ham, Stoke and Huddersfield as well as Celtic, it contributed to taking Jonathan away.

Occasionally, people tell him that returning to coaching would be what his son would have wanted, but Macari doubts that. These same people assured him that time would heal everything and they were wrong about that. Something inside Macari went missing that fateful day nine years ago and he never expects to find it.

Lou Macari: Football My Life (Bantam Press, £18.99)