The pair go back a long way. Warnock was a winger at Barnsley when McCarthy was an apprentice.
Warnock said: "We know each other very well. Mick used to clean my boots at Barnsley even though he denies it now. He was the only 15-year-old I've seen who was 6ft 4in. All the other kids were midgets next to him.
"Mick was the leader, he was like Arthur Scargill and being in Barnsley that was appropriate. Not only was he bigger than the other lads but he talked like a 50-year-old too!
"But he still had respect and good manners — and made sure the other young lads never stepped out of line. If they did, Mick would sort them out. He was built like a brick you-know-what.
"He denies he cleaned my boots but he did and, in those days, it taught the young lads respect.
"Now it's all about human rights and the PFA have rules on what you can and can't do with apprentices."