Glenda Jackson appears briefly in the group singing round the piano at the Christmas party.
When Richard Harris is roughed up behind the scrum, rugby league legend Derek Turner, who was playing the character who punches him, was asked by the director to make the contact look real. So he did. He punched Harris for real and knocked him out completely, shooting for the day had to be stopped while Harris recovered.
Because the budget would not stretch to the thousands needed for the rugby league match scenes at Belle Vue, director Lindsay Anderson deployed hundreds of wooden dummies to stand amongst the human extras for the crowd scenes.