Smith insists it should be the quality of the players rather than their age which dictates whether they deserve a first-team opportunity.

He included Steven Lennon, Jordan McMillan and Steven Kinniburgh among his seven substitutes for the league opener at Inverness, and then Lennon, McMillan and Paul Emslie for Saturday's Ibrox clash with St Mirren.

None of the youngsters got any further than the bench however, while more established but older players sat in the stands, with Smith prevented from including them.

He claims the ruling rewards age rather than achievement, and has disputed the sense in keeping it in place.

He said in club magazine Rangers News: "I feel that the under-21 ruling pushes you to put a young player in there and lets them think they've achieved a certain level without them actually doing anything to achieve that level.

"We've had young players come in to our team over the years - Barry Ferguson, Charlie Miller and Steven Pressley, for example - and every one of them has done so regardless of their age.

"In the next few years I'm sure we will have several young players here pushing their way into the first team but they won't do so because they are under 21 but rather because they are good footballers.

"That should be the criteria for picking a team, not because of someone's age.

"A lot of younger players are getting involved in first-team games far too easily simply because of their age and not because they're making the demands of football. That's wrong."

Smith argues that the SPL rule is making it too easy for young players to feel involved as members of the senior set-up.

"It's a nonsense that a player gets his involvement due to his age rather than his ability," he said.

Charlie Adam, who hit 14 goals from midfield for Rangers last season, was a spectator for the St Mirren match, while summer signing Alan Gow was another who missed out, when Smith would rather have had both players on the bench.

He argued: "It would be better if the players could feel like they were involved, even as a substitute.

"As it stands just now you have to leave out reasonably experienced players who then feel like they're not getting any opportunity to get close to the team."

Smith is likely to be supported in his view by Celtic boss Gordon Strachan.

Faced with a similar situation, where fit senior players were missing out, Strachan said at the start of last season: "I think the rule needs to be looked at."