It was the afternoon of the Old Firm game, Rangers v Celtic at Ibrox, Saturday January 2 1971.

The match was heading for a 0-0 draw when Jimmy Johnstone broke the deadlock to give Celtic the lead in the 89th minute.

Then, with just seconds left on the clock, Colin Stein snatched a dramatic equaliser for Rangers.

The blue section of the 80,000 all-ticket crowd went wild with delight. The green was thrown into despair.

Two goals in a minute. What a finish! Yet, unseen amid this sea of emotions, a disaster was beginning to unfold at the Rangers end of the ground over on the East terrace at Staircase 13.

As the fans swayed away from the heaving mass, some stumbled halfway down the steep steps. Those around didn't see them fall and continued their descent.

Suddenly a tidal wave of fans was engulfed in a terrifying crush. Steel barriers crumpled under the impact.

When the carnage cleared, 66 people had lost their lives and more than 140 lay injured.

Among the dead were 31 teenagers. The youngest victim was a boy of nine, Nigel Pickup, who had travelled to the game from Liverpool.

One woman was among the fatalities. Margaret Ferguson, an 18-year-old from Maddiston near Falkirk, had made a doll for the baby daughter of Rangers centre-forward Stein - the man who scored the late equaliser - and had delivered it to his home just before Christmas.

Five schoolboy pals, four of whom lived in the same street, had gone to the game together from the small town of Markinch in Fife. The five, all members of Glenrothes Rangers Supporters Club, never returned.

There were so many harrowing tales. Eye-witness John Dawson was among the injured. He said: "When the barrier gave way I was carried along a passageway for 20 yards with three people on top of me and at least three underneath."

Another survivor of Staircase 13 was Robert Black. He said: "There was so much pressure from behind me that I was tossed down on top of others. People were on the ground and I was tossed over them. I was just carried forward by the surge."

Both sides of the Old Firm put aside their rivalries and came together to play a game to raise funds for the victims' families. A combined Rangers and Celtic team took on a Scotland XI at Hampden watched by 81,405 fans.

The tragedy echoed a previous accident on Staircase 13 when two people had been killed.

The club and their fans were in mourning. It was the blackest day in the history of Scottish football.