He may have reached the age where many others are starting to wind down, or contemplating a few more lie-ins, but Alexander Chapman Ferguson will delay any celebration of his 70th birthday until after his Manchester United players have completed the significant business of attempting to wrest three points from Blackburn Rovers' grasp at Old Trafford this afternoon.

Even after spending more than a quarter of a century in Manchester, where he has steered the Old Trafford club to unprecedented silverware, including two Champions League trophies and a dozen championships, Ferguson and the city of his birth are so inextricably intertwined that it is impossible to imagine one without the other.

When he was growing up, working-class Glasgow was defined by the shipyards, trade unionism and football. Even as a youngster, his commitment to education, Old Labour principles, and forging friendships that have endured to this day, embodied his devotion to a world that may have vanished, but to which he remains forever welded.

That also explains why it is better to have him as a friend than an enemy, and underpins why this tough-as-teak character still turns up at the United training ground early every morning and refuses to countenance any relaxation of his grip on a club he transformed from being a near laughing stock in the late 1980s into the most successful side that has ever paraded its powers in British football. None of it happened by accident.

Ferguson's gruff demeanour and cantankerous responses to "silly" questions at press conferences have left several English commentators remarking that the spirit of Jim Taggart is alive and well in Manchester.

But reflect on this: here is a character who suffered rejection at Rangers and witnessed the club's anti-Catholicism in the guise of their public relations officer, Willie Allison, whom he branded a bigot, and yet Ferguson transcended the indignity of leaving Ibrox as a failure by becoming arguably the greatest manager in the history of the sport. He had to leave his roots to orchestrate his hallelujah trail, but his relentless drive, perfectionism and desire to be the best yielded undreamt of success at Aberdeen, who famously won to the European Cup-Winners' Cup in 1983 and grew accustomed to beating both halves of the Old Firm, such was Fergie's influence.

He could have returned to Rangers in a managerial capacity, but instead chose the bigger challenge of resuscitating a Manchester United squad who had become better known for their nightclub carousing and Bacchanalian excess than their performances on the pitch. So he weeded out the miscreants, recruited his own personnel and, oblivious to his early travails in England, gradually, inexorably, stamped his imprimatur all over his domain.

In the process, Ferguson made enemies, deflated plenty of egos and occasionally strayed into spats which, at this distance, seem slightly absurd; remember Pizzagate and his long-term feud with Arsene Wenger?

However, fuelled by an instinctive mistrust of people who basked in comfort zones rather than put their bodies through the wringer to make the most of their talent, he almost single-handedly dragged the English game kicking and screaming into the 21st century.

One of his central tenets has always been, "at the end of the day, the bus goes on and we don't wait for anybody", but sometimes he has tolerated a player's idiosyncrasies, as in the case of Eric Cantona, if he considered them to possess special gifts.

In other circumstances, he was a surrogate father to the likes of the teenage David Beckham, who was painfully homesick in Manchester, yet persevered in practising his free-kicks even as he fought back tears. All the while, Ferguson's man-management skills were based on the same convictions that had made him a potent shop steward in his youth. "I am careful of the players I lay into," he once said. "Some can't handle it. Some can't even handle a team talk. There are some I don't look in the eye during a team talk because I know I am putting them under pressure."

Yet, ultimately, the greatest attribute of this knighted Scot is his refusal to stand still and his belief that if you master the minutiae, the bigger picture looks after itself.

At 70, others might feel intimidated by the emergence of the lavishly-bankrolled Manchester City, and Ferguson confessed to embarrassment after his side were thrashed 6-1 when the clubs locked horns in October. But it is a measure of his motivational skills and indefatigability that no amount of disappointments or travails can dent his enthusiasm for football and his determination to keep pursuing fresh tilts at honours.

If United beat Blackburn today, they will be at the summit of the Premier League. And only a brave man would wager against them being there at the end of the campaign.

"The most important thing is the work ethic," could be the message etched on his office door. It doesn't always make him easy company, but then life wasn't easy when he was growing up in Govan and he has never forgotten that truth. Few in his homeland will be more justified in allowing themselves a quiet drink this evening.