No-one needed convincing that Manchester United boast a huge following in Ireland but the extent of that fandom was quantified this year with findings put together for an Atlas of Irish Sport declaring that over 550,000 adults here owe an allegiance.

It's a relationship as long as it is deep.

The Munich disaster in 1958 brought with it a sympathy throughout the football world that morphed into ever stronger feelings of support. Matt Busby's capture of the elusive European Cup a decade later, with another thrilling side, added a further layer of romance and one that was heightened for another generation by Alex Ferguson's imperious stint in the Old Trafford dugout.

Too often forgotten is the first flowering of real passion here.

Go back ten years before so many of the Busby Babes met such a shocking and premature end and the Scottish manager's first stab at greatness with the club produced a side that captured the 1948 FA Cup and one that would finish runners-up three times across four years in the First Division before claiming the title in 1952.

That in itself was no decisive reason for Irish football fans to declare their love. The pinnacle of English football was a more democratic, and distant, landscape then. Seven different clubs would win the title in the nine years after World War II, eight different clubs would lift the FA Cup in the same period and players whose names still merit reverence populated its pitches.

Stanley Matthews and Stan Mortensen starred at Blackpool. Billy Wright was captain of Wolves and England. Newcastle United's 'Wor Jackie' Milburn was a forward of rare productivity and there was the genius that was Tom Finney with Preston North End. What United had that others didn't was such a notable Irish link in their captain Johnny Carey.

There are any number of achievements that frame 'Gentleman John's status in the game: first Irishman to lift the FA Cup; first 'foreigner' to skipper the English league winners; Football Writers' Footballer of the Year in 1949; captain for Ireland when they became the first country outside of the Home Championship to beat England on English side that same year...

On and on it goes.

His obituary in the London Independent after he passed away in 1995 captured his greatness without recourse for a CV. It started off: “Johnny Carey was a thoroughbred footballer who exuded class and calmness as Manchester United's first post-war captain and one of the most accomplished full-backs the British game has produced.”

The United side that he brought back to his hometown in 1948, on a recently introduced Aer Lingus service, included standout talents such as Jack Crowley and Charlie Mitten. United had ended the season with 103 goals scored and lived up to their billing on tour by fielding sides that boasted most of those who had overcome Blackpool 4-2 at Wembley at the end of April.

Few cup runs have ever topped it. Six top-tier clubs were beaten on the way. Of them, Liverpool would finish the furthest down in that year's league table, in eleventh, and they were the reigning league champions. United scored 22 goals across their half-dozen cup games, the last three coming in the closing stages of the decider having trailed 2-1 as late as the 70th minute.

Almost 100,000 people saw Carey accept the cup from King George VI. A similar number took in their trio of fixtures against select sides representing Bohemians, Shelbourne and Linfield. They started with a 2-1 loss at Dalymount Park to a Bohs 'team' that featured seven guest players, four of them Blackpool players defeated so recently in the London showpiece.

They would have their revenge with three of them, Eddie Shinwell, Harry Johnston and Eric Hayward, manning an impressive rearguard in the first-half before United took the lead through Mitten. Brendan O'Kelly, one of the 'Bohs four' and a Harvard graduate who played for Ireland at the Olympics that year, equalised soon after.

The winner came two minutes from time when, with Johnny Morris and Ronnie Burke denied decisive goals at one end for the visitors, the home team broke upfield. United keeper Jack Crompton denied Kevin O'Flanagan, then of Arsenal and formerly of Bohs, only to see the attacker's brother Mick sweep the loose ball home.

'Dramatic goal beats the English Cup holders,' was the headline on the Irish Press the next day but the tourists would follow it with a 4-3 defeat of a Shels selection four days later and a 3-2 win over Linfield to round out the trip in Belfast. United had won over hearts and minds with their football and there was a hint of the affection they had earned in the papers.

An Irish Independent reporter expressed a satisfaction with the result against Shels given it was “what most if wished for the Cup holders [who] have won a place in the hearts of the Dublin public”. John DT White, who wrote the book 'Irish Devils' just under a decade ago, certainly saw the tour as an augury for what was to follow.

“If there was a moment when you could say that the Irish love affair with Manchester United really began, it is arguable that it was now," he wrote. "United had just won the world's most famous cup competition, they were captained by an Irishman ... and what's more they had taken the trouble to come to Ireland to show everyone what they could do.”

It's not an untouchable claim. English clubs were no strangers to these shores. Everton, Luton Town and Newcastle United were doing the rounds in Ireland at the same time but United had at least laid solid foundations for a relationship that would only ever get stronger.