Several objects were thrown by Celtic fans, one of which struck referee Hugh Dallas forcing the game to be stopped while he received medical treatment.[55][2][3] With many of those in attendance having spent a full weekend drinking alcohol prior to the event, at least four Celtic fans invaded the field of play to confront Dallas during the game,[55] and more missiles were thrown at players on the pitch after the game.[55] Since the events of that day, Old Firm league matches have normally been played in the early afternoon and the possibility of an Old Firm title decider has been deliberately avoided.[56]