It was an emotional moment on Saturday May 17th 1969 when the referee blew the whistle to end Manchester United’s final match of the season.

Not because of the score – United had seen off Leicester City 3-2 with goals from George Best, Denis Law and Willie Morgan.

And not because United had won the league – or even come close. They finished 11th.

The Old Trafford faithful had invaded the pitch in their thousands for another reason.

An emotional Sir Matt Busby in the players’ tunnel at Old Trafford, May 1969

An emotional Sir Matt Busby in the players’ tunnel at Old Trafford, May 1969

They wanted to say farewell to a football icon – United manager Sir Matt Busby.

The man who’d rebuilt his team after the Munich air crash and brought the European Cup to Manchester was stepping down after 24 years at the helm.

Cheers thundered round the stadium as Busby walked through the players’ tunnel back on to the pitch after the game. They were witnessing, or so they thought, the end of an era.

Busby’s legacy was immense. Five First Division titles, two FA Cups, five Charity Shields and the European Cup were won on his watch.

Police keep the crowds at bay at United’s last match of the season, May 1969

Police keep the crowds at bay at United’s last match of the season, May 1969

He’d also reached the semi-finals of the 1969 European Cup, going out 1-2 to AC Milan after a Denis Law goal had been disallowed.

Amid all of this, he’d battled back from despair after the Munich air disaster had decimated his beloved team of ‘Busby Babes’ on February 6th 1958.

It was little short of a miracle that he survived that ghastly night. He was read the last rites twice as he lay helpless in a Munich hospital bed.

Doctors kept the news from him that 23 had perished in the crash, including players, officials, press and supporters.

Time to go - Sir Matt Busby announces resignation at an Old Trafford press conference, January 1969

Time to go – Sir Matt Busby announces resignation at an Old Trafford press conference, January 1969

He learned the truth from a Franciscan friar three weeks later while he was still recovering in hospital.

Busby was so affected by the Munich tragedy that he nearly gave up football altogether. It was his wife Jean who persuaded him to persevere – in honour of the players who died.

He would have felt the memory of those players all the more keenly as the crowd sang his name at Old Trafford on the final day of the season.

Preparations to find his successor had started soon after United beat Benfica 4-1 at Wembley in May 1968 to become the first English team to win the European Cup.

Bobby Charlton and Sir Matt Busby with host Eamonn Andrews on This Is Your Life, November 1969

Bobby Charlton and Sir Matt Busby with host Eamonn Andrews on This Is Your Life, November 1969

In January, a press conference at Old Trafford revealed that Busby would step down as first team manager at the end of the 1968-9 season.

He would remain as general manager with Wilf McGuinness taking over the first team.

On paper, McGuinness seemed a good choice. Born in Manchester and a former United player, he’d learned the ropes as reserve team manager under Busby since 1964.

At 31, he was young for such a major position – but Busby would be on hand for help and guidance.

George Best proudly shows Sir Matt Busby his European Footballer of the Year award, July 1969

George Best proudly shows Sir Matt Busby his European Footballer of the Year award, July 1969

Busby began his general duties on a happy note. In July 1969 he was on hand to witness George Best receiving the European Footballer of the Year award at Old Trafford.

In December he was guest of honour when Bobby Charlton was ambushed by TV host Eamonn Andrews to be the subject of the biographical show This Is Your Life.

But while things were going smoothly off the pitch, cracks were starting to show on it.

United lost the opening match of the 1970-71 season to fierce rivals Leeds United at Old Trafford and could then only manage a goalless home draw with Chelsea.

Denis Law’s goal against Milan is ruled out by an unsighted referee, May 1969

Denis Law’s goal against Milan is ruled out by an unsighted referee, May 1969

A 4-0 thrashing by Arsenal at Highbury was the precursor to two consecutive home defeats in December. United went down 4-1 to Manchester City and then 3-1 to Arsenal.

The board had seen enough. Busby was called back to run the first team and McGuinness resumed his former role of reserve team manager.

Six months later, Busby retired for the second time when Leicester City’s Frank O’Farrell took over as club manager.

He remained a director for 11 years before being made club president in 1980.

The European Cup paraded by George Best and his team mates at Wembley, May 1968

The European Cup paraded by George Best and his team mates at Wembley, May 1968

Sir Matt Busby salutes the Old Trafford crowd at his final game as team manager, May 1969

Sir Matt Busby salutes the Old Trafford crowd at his final game as team manager, May 1969