On derby day Ibrox is a tumultuous, seething cauldron of vocal emotion. But not long after midday tomorrow the ground and its more than 50,000 occupants will fall silent and the players clad in familiar hues of blue and green will surround the centre circle; for a minute there will be no sound or fury, only emotion.
On 2 January 1971 one woman and 65 men and boys were killed on Stairway 13, the steep exit that ushered spectators out of the Copland Road end of the stadium housing the home support. For the traditional New Year Old Firm game 80,000 fans had shoe-horned into the ground; it ended with bodies laid on the pitch, the wounded treated in the dressing room and comforted by Jock Stein, the Celtic manager.
John Greig was captain of Rangers that day. "I was one of the last people to come out of the dressing room because I'd got a slight injury and had been getting some treatment and they started to bring one or two bodies into the dressing room," he said. "It's an unreal situation to see that. I walked down the tunnel and saw the bodies lined up along the side of the pitch. It was a cold, foggy day and it's something that never leaves you. It's etched on my mind and will always be there."
Tomorrow Greig and Billy McNeill, his Celtic counterpart from 40 years ago, will lead out the teams, who will wear black armbands, while the Rangers side will also be kitted out in commemorative jerseys.
"It will be a proud moment for Billy," said Greig, who played for and managed Rangers before becoming a director. "It will be a very proud moment for myself, and a very humbling moment. Sometimes I wonder where all the years have gone. The years have gone so quickly. Particularly at this time of year, you can't help but think about what happened 40 years ago. It was a sad, sad day and something you never forget."
Among the crowd in the Copland Road end was Walter Smith, now manager of Rangers, then a young player on Dundee United's books, who two weeks later was to play in the first game at the ground post-disaster. "You just feel fortunate," he said, "when you are that close to something like that, that you get out without coming to any harm. I consider myself very fortunate."
Smith and his brother headed down the stairway after Celtic had scored in the final minute. Others, too, departed and the stairway was crowded when Rangers equalised almost on the final whistle. Some have blamed supporters trying to get back into the stand on hearing the cheers for the equaliser, but it seems more likely that someone slipped – one story has it a father with his son on his shoulders – and what followed was grimly inevitable. A section of the railings buckled and collapsed. Eyewitnesses spoke of bodies piling up. The victims were asphyxiated.
"Never again," vowed Willie Waddell, the Rangers manager. It led to Ibrox being comprehensively rebuilt, albeit over a decade, and by 1981 they had one of the first all-seated stadiums in the UK. It took a disaster to bring change, but not throughout the sport. It took another, more costly, tragedy at Hillsborough some eight years after the new-look Ibrox was completed for the crumbling, perilous state of many of the nation's grounds to finally be dealt with properly.
"It's a very emotional time of year and, at New Year, I have always laid a wreath to remember those people," said Greig. "I know it's a time when people enjoy themselves but you can't dismiss something like that. If someone gets killed in a car smash, you can't understand it but you have to accept it. But for someone to go to a football match and not return, it's a terrible, terrible thing."