Manchester United legend Bryan Robson says manager Sir Alex Ferguson's ruthlessness has been key to his success.
Robson is full of admiration for the way Ferguson has continued to build winning teams at United.
He told the Sunday Mirror: "Sir Alex is amazing like that. Always was. As soon as something triggers in his mind that he thinks it is time for a player to move on, he does it - and you will not change his opinion on it.
"He will be adamant that he has maybe seen just a little bit of a flaw in a player, and as soon as that happens he'll try to replace them with younger ones."
