"I understand it. I get it," he said.

"When I do have to make those decisions at least the players will know I do have empathy with them, because I have been in that situation myself.

"There is a long way to go before you get there, so I am not going to beat myself up for the next six months wondering what is going to happen, because players will get injured.

"It will be a really tough decision. But one that, if I am being honest, I look forward to making, because that's my job."

Clarke picked up six caps for Scotland between 1987 and 1994, but despite consistently turning out for Chelsea in the Premier League he didn't make the cut for the 1990 World Cup squad, nor the Euros in 1992 and 1996.

He also missed out on the squad for the World Cup in 1998 where, despite being in his mid-30s by that point, he had been part of Chelsea's League Cup and Cup Winners' Cup winning squad.

"The 1990 one was actually closer than 1998 because by that time I had more or less given up," he said.

"Craig Brown did cap me in 1994 against Holland in the last game before they went to the World Cup.

"But I just felt that between 1994 and 1998 I was playing some of the best football I ever played because I was playing with better players and I was in a really good place.

"I felt my versatility might get me into the squad, but Craig Brown had other ideas. I didn't really understand at the time. But now I understand completely."

Clarke has been regarded as very loyal to his Scotland players, but with the likes of Tino Livramento and Elliot Anderson at Newcastle emerging as eligible contenders for the squad, he says there will be much more under consideration than previous performances for the national team.

"Loyalty is part of it, but with that loyalty must come performances," he added. "So long as they are performing for me and for the country then the loyalty can be rewarded. If the performances are not there it's more difficult to be loyal.

"It's going to be a difficult 23-man selection."