The Old Firm game takes care of itself. More clichés are flung at it than tackles and it is, by far, the biggest club game in the world-only in this corner of the world. This one was the biggest of the biggest, not least because it fell exactly 40 years to the day after stairway 13 collapsed at Ibrox under the combined weight of fans leaving after Celtic had scored with a few minute to go and Rangers equalising just before the final whistle and...