The Daily Record reports that a memo from a superintendent said there was a “clear link” between Celtic choosing to have a lap of honour around the ground and the reaction of the Rangers fans.
Following their 1-0 victory, the home players continued their applause even when they reached the Rangers section. Several angry supporters then piled to the front as stewards and police tried to hold them back.
The away fans had been locked inside the ground for 15 minutes after the game to allow the crowd outside to disperse.
The memo read: “I am firmly of the view that there is a clear link between the actions of the Celtic players (which immediately inflamed an already delicate situation) and subsequent response of the Rangers fans.
“Had I known about the Celtic team lap of honour, I would have suggested that the plan would be to release the Rangers fans first, if we had a Celtic win.
“As it was, as the Rangers fans had already been informed of the holdback, not many were actually making concerted efforts to leave so the timings to change the cordons etc round and deliver comms and messages were too tight.”