"There was one moment in my life when he took time to phone my mum," Nicholas said. "I was working as a car mechanic and Billy said: 'I'm going to phone your mum, I want you to become a professional'.

"My mum hated the prospect of it but he phoned her and said: 'Don't worry, he will be fine. He will play for the first team, he will make a career'.

"Just that time he took still sits in there," Nicholas added, pointing to his heart. "I don't mind crying for Billy, but it sums up what he was."

Frank McGarvey, who played under McNeill during the early 1980s, told Press Association Sport: "He was loved by all the players and you don't hear that about all managers.

"He won a lot of trophies with Celtic on and off the pitch but not only that, he was a great person, a fantastic man. He would do anything to help you. He will be sadly missed."

Another ex-Celtic player, Davie Provan told Sky Sports News: "He was a terrific man-manager, really fair with the players. He backed the players. Within a year of coming back to Celtic he managed to get the players' wages doubled.

"Nobody was in any doubt as to who the boss was, we all got the sharp end of his tongue when we needed it. But overall a terrific man-manager and a terrific human being as well."

Tributes came in from the likes of Rangers and Inter Milan, the latter remembering a "great opponent" from the 1967 European Cup final.

Former Gers striker Sir Alex Ferguson, who succeeded McNeill as Aberdeen manager in 1978, told the Celtic website: "He was a giant in Scottish football, a man with an incredible presence and I'll always cherish the fact that we entered professional football at the same time.

"We played against each other on many occasions and, as anyone who played against him will testify, he was the fairest of players.

"He was also a truly good man and will be a loss to everyone who knew him. Farewell Cesar."

McNeill's current successors as Celtic manager and player also paid tribute.

Manager Neil Lennon said: "I love Billy's statue, which is the first thing you see whenever you walk up the Celtic Way. It's the perfect image of him, holding aloft the European Cup, and it will remind future generations of supporters of what a great Celtic man he was."

Skipper Scott Brown added: "Billy set the benchmark as a Celtic player and captain, and that's something everyone who pulls on the jersey has to aspire to."

Celtic chief executive Peter Lawwell said: "It has been one of the great privileges of my life that, over the years, I got to meet and know Billy, not just as a great Celt, but also as a great man and someone I was delighted to call a friend.

"His presence on a matchday here at Celtic Park, where he would cheer on the team, was always a great opportunity to meet up with him, and it was also an indication that he always was, before everything else, a Celtic supporter, faithful through and through.

"This is the saddest of days for the Celtic family, and also for the wider football world. We mourn Billy McNeill's passing and we send our thoughts and prayers to his family and friends, while we also give thanks for Billy's life and the incredible joy he brought to so many people as a Celtic player, a Celtic manager and a great Celtic man."

McNeill won 29 Scotland caps and the Scottish Football Association also paid tribute.

SFA president Alan McRae said: "The Scottish football family has lost one of its all-time greats. Billy was, quite simply, an icon of Scottish football – a natural leader who, though synonymous with Celtic, was respected throughout the entire Scottish footballing fraternity.

"Though the man known as 'Cesar' to Celtic fans is predominately known for his club career, his Scotland career also saw him help the team to new heights – in his first match as captain of Scotland he led the team to a 1-0 victory over England in front of more than 133,000 fans at Hampden Park."

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