It is time to wish 'Gentleman' John Clark a belated happy birthday.

The Lisbon Lion turned 74 on Friday and can still be found at Lennoxtown most days, helping out with the Celtic kit and encouraging the club's development squad. A life of success and tragedy has shaped Clark, though no-one quite knows where his unfailing modesty and courtesy spring from.

When Clark was 10 years old, and tearing around the environs of Airdrie like any wee kid in the 1950s, terrible news was wrought upon him.

"I remember the moment clearly, it was a Saturday morning, just a few days before Christmas," he said. "These two policemen arrived at our door and I knew something was wrong. My father was a railwayman and he'd been away checking on faults down near Watford. My mother took one look at these policemen and said to me, 'John, go outside and play, would you?' I went outside and then heard my mother's cries from inside the house.

"My dad had been killed by an onrushing train. He'd been working on the tracks and a signal was supposed to operate, but it never did. The train appeared from nowhere and killed him instantly. It left my mother a widow, with two young kids, and six months pregnant with another. I'll never forget that day."

Lisbon in 1967 and being made a king of European football was still 16 years away for Clark. From that tragic episode onwards, the wee Lanarkshire kid would scrap and survive the hard way. Maybe not so amazingly, Clark combined his gentleness of character with a tough-as-nails instinct to survive.

"My life became pretty hard," he said. "The family earner was dead and I had to go out and get work. I got a job at a pit-head in Airdrie, and I took another job helping a local farmer sell eggs and potatoes around the area. There was no other option. My mother needed the money. My dad's death taught me that life would be tough, and that I had to keep going."

Further fate, of course, would turn John Clark from a Lanarkshire waif into European footballing royalty. In 1958 Jock Stein was in charge of Celtic's reserves and he liked the look of the wee, squat, determined sweeper he'd seen playing for Larkhall Thistle. Clark was signed up for Celtic aged 17 and, nine years later, he became one of British football's immortals.

The afternoon of May 25 1967, when Celtic beat Inter Milan 2-1 to win the European Cup, is a moment cherished and handed down by generations of Celtic supporters. Clark was sweeper beside Billy McNeill that day and, without fuss, calmly saw off various Inter forays.

"We were an incredibly confident bunch of guys," he says. "We knew we could win it, we had no fear of anything. We just fancied ourselves rotten. Inter were meant to be the best club side in the world at the time but we thought we'd beat them. Even at half-time and 1-0 down, nobody panicked, no-one thought anything negative. Big Jock told us nothing remarkable, he said, 'just keep playing, you'll get there.'

"We were ultra-confident in our ability. We knew we had it in us. Looking back it sounds a wee bit like arrogance. But we never believed we'd be beaten that day in Lisbon."

Clark was 26 at the time, but his Celtic career was soon to be cut short. In fact, checking the record books, it is shocking to see how soon he was displaced by the new, young talents coming through at Celtic Park.

"Not long after Lisbon - maybe 18 months later - I got a cartilage injury in my left knee which destroyed my career. Nowadays you come back from these things in five minutes, but not back then. I was out for nine months and when I came back my knee was never the same again.

"I remember the moment very clearly. Big Jock used to send us here, there and everywhere to play, and we were at the old Bayview playing against East Fife. The ball came to me in the box, I turned away with it, and this guy just came right through me, the full brunt of his weight on my knee.

"That was it for me. I was in and out of the team after that, but I was never the same again. The injury finished me."

It is well-known in football how much John Clark deplored some of the fame and celebrity that came his way. His daughter, Marie, an adult education teacher, remembers how her modest father disliked the profile that came with his football career.

"My dad is fundamentally a shy man," she says. "He never wanted the fame that came with playing for Celtic and was never comfortable with it. At Celtic there were guys like Billy [McNeill], Berti [Auld] and Jimmy Johnstone, but dad was not outgoing like these guys.

"I remember sometimes as a wee kid I'd be out with him and someone would want his autograph. Of course, he would give it, but it just wasn't in his nature. In his day the press never attached themselves to my father because there was no story there. He was just a family man who did his training and then went home."

Clark himself says: "I never wanted any of that [fame or celebrity]. It wasn't me. I preferred being in the background. Big Jock used to say to me, 'push yourself forward, be more up front.' I just said, 'no thanks'.

"But I've no complaints. I had a great career and I've got a great family. My life turned out to be very, very good."