Celtic great George Connelly on facing Leeds United in front of a European record crowd of 136,505 at 21

A crowd of 136,505 – a record attendance for a UEFA competition that will never be broken - crammed onto the terraces at the world-famous Mount Florida ground to see the meeting between Stein’s celebrated side and Don Revie’s revered and feared team.

Yet, the Celtic manager still selected two members of the so-called Quality Street Gang – George Connelly and his good friend Davie Hay – in his starting line-up alongside the likes of Bertie Auld, Tommy Gemmell, Jimmy Johnstone, Bobby Lennox, Billy McNeill and Bobby Murdoch despite the enormous turnout and the intimidating atmosphere.

His boldness paid off. Celtic, leading 1-0 from the first leg at Elland Road a fortnight earlier, performed brilliantly and recorded a famous 2-1 victory to book a place in their second European Cup final in four years.

Connelly, who had only turned 21 the previous month, was delighted but unsurprised to be given the nod that night. He had, after all, scored the only goal of the first meeting with Leeds in the very first minute. However, he also knew Stein had always, regardless of the magnitude of the occasion, been unafraid to field kids if he considered they were talented enough.

“Jock Stein gave Alex Edwards his debut for Dunfermline just five days after his 16th birthday when he was manager at East End Park,” he said. “Jock was like that, he always gave young players their chance.

“But I got brought in gradually by Jock. That is the secret with young boys – bring them in, give them a chance, put them back in the reserves. Let the fans see what’s coming through, but don’t play them too much. Young kids are growing. When I left school I was 5ft 8in. I ended up about 6ft 1in.”

Connelly must have felt about 10 feet tall when he netted just 40 seconds after a double header which had been dubbed The Battle of Britain by the press got underway down in Yorkshire. “I scored with my second touch,” he said. “It nicked Paul Madeley’s shin guard and spun into the net. It was a lucky goal.”

There was, though, nothing fortunate about the 3-1 aggregate scoreline. Auld, Connelly and Murdoch took complete control of the midfield from kick-off in the rematch. Winger Johnstone, meanwhile, had what many shrewd judges believe to be his finest 90 minutes.

The long-range piledriver that Billy Bremner rifled in from fully 25 yards out to put the visitors ahead in the first-half was very much against the run of play. Second-half goals from John Hughes and Murdoch ensured a richly-deserved triumph.

Connelly has fond recollections of the occasion 50 years on. “I thought there were more people there than the official attendance,” said Connelly. “I think there were about 20,000 who broke in that night. I can remember walking out on the park and saying: ‘What a crowd!’ That was awesome that game.”

Revie’s men were known as “Dirty Leeds” at that time. With some justification. In Bremner, Jack Charlton, Johnny Giles and Norman Hunter, who were all involved at Hampden, they had individuals who frequently overstepped the mark with the robustness of their challenges. But Connelly saw no evidence of that side of their play.

“Leeds were practically invincible at that time,” he said. “Nobody thought Celtic had a chance. But we beat them in both games I was involved in both games. They had this reputation of being hatchet men. But in those games they let us play and we let them play.”

Connelly, a cultured and technically gifted footballer who was comfortable and effective in a variety of positions in defence and midfield, was one of a crop of outstanding youngsters, which included Kenny Dalglish, Hay, Lou Macari and Danny McGrain, who emerged at Celtic in the late 1960s and early 1970s.

He can recall how they spurred each other on. But he can also remember how the Lisbon Lions, the team that had beaten Inter Milan to win the European Cup in 1967, had helped them too. Their talismanic captain McNeill especially.

“The likes of Danny, Kenny, Loui, Davie and myself all came through at the same time,” he said. “We were playing with the Lions so we had something to live up to. They were a hard act to follow.

“But playing with those guys helped you. They made it easy for you because they were such great players and great professionals. We learned every day training with them and playing with them. It is great to have good professionals in your side when you are a young boy. You depend on them.

“I had a good relationship with Billy (McNeill). He was my idol when I was at school. He was a Celtic icon wasn’t he? The Lions were built around him. In my opinion, he is the greatest Celtic player of all-time.”

The football landscape has changed beyond all recognition since that halcyon era and the Celtic team of today is no longer able to compete with the biggest clubs in England, France, Germany, Italy and Spain for major continental honours due to the size of the broadcasting deals in those major football nations.

Connelly, now 71 and living in Clackmannan just outside Alloa, still takes an interest in how his old club are faring. He believes there is still much to be gained from giving youth academy products their opportunity in the first team.

He has been pleased to see current manager Neil Lennon give game time to the likes of Karamoko Dembele, Jeremie Frimpong, Ewan Henderson, Mikey Johnston, Scott Robertson and Stephen Welsh since returning to Parkhead last year.

“They should keep the young ones coming through and mix them in with the odd player they have bought,” he said. Basically, they should just keep doing what they’re doing. They have a nice mixture, a good balance.

“The young kids who are coming into the team now have Scott Brown to help them along. They look up to him. The manager will look to the older players to help bring them through.

“I was always interested when Kenny was playing, Danny was playing, Davie was playing, Lou was playing. You took encouragement from that. The young boys now will the same. They will be saying: ‘If he can do it I can do it’. If they have got the ability the manager will put them in. Lennon isn’t scared to put them in either.

“I am sure Lennon will do with Dembele what Jock did with me, give him a few games, put him back in the reserves, let him build his strength up, gradually bring him in. It worked for me.”

Celtic’s Lost Legend - The George Connelly Story by George Connelly with Bryan Cooney is published by Black & White Publishing and costs £9.99 in all good book stores.