A mercurial talent. His loyalty to Celtic was culpable in preventing a big move south. Had he done so, he would be talked about as one of the all time great Scottish (and British) players.
Don't think he was ever going to leave Celtic his family connections go right back to the formation of the club, there was the reported Inter Milan transfer which didn't materialise, a brilliant player and definitely world class, he carried the Celtic team for years on his own most of the time until Collins arrived.
Danny McGrain was another world class player and one club player he's basically spent his entire adult working life at Celtic.