Roy Keane | When the Man United legend signed for Celtic | Memory lane Monday HD

Roy Keane turned down Real Madrid to sign for Celtic in December 2005, a decision he would later admit that he regretted. The pull of Celtic, however, was strong for Keane, who was searching for a new football home after his turbulent exit from Manchester United. Yet, his time at the club would prove to be an anti-climax at the end of a stunningly successful playing career. He would also say that he is now “a bit embarrassed” by his time with the Glasgow club.