Gordon Strachan says the booze culture at Old Trafford probably cost Manchester United silverware during the 1980's.
The Celtic manager told the Sunday Mail: "It was a problem. Players just couldn't recover from injuries quickly when they were drinking that much.
"I am now obsessive about the off-field activities of my boys. But it is only because I am trying to get the best out of them. They're like children sometimes.
"You look after them and they get annoyed with you but you are only looking after their best interests.
"I am looking to their future. Not just to play for a year for me but so they can play until they are 36 or 37.
"Guys I played beside such as Gary McAllister, Gary Speed and Ray Wilkins played to a good age because they cared for themselves."
