YOUTH development is a work in progress at Dundee United.

It is resumed each morning at 8am when Stevie Campbell arrives at Tannadice, the club's director of youth engaged in unlocking the potential of those players under his charge, but only once he has found the key to the front door.

It is an early start but one that has become as much a routine for the 45-year-old as guiding United's best and brightest young players towards success, with Ryan Gauld last night taking another step by gaining his first call up to the Scotland Under-21 squad ahead of the UEFA European Championship qualifier against Georgia. That helps to describe the promise shown by the 17-year-old this season but it is perhaps articulated better by Campbell, since he does not expect Gauld to still be at the club in two years despite the forward signing a contract extension until May 2016.

It is the sort of comment which can cause fans to fall silent and the coach has been working to ensure that United's academy does not go quiet as well; the list of young players making their way through the age groups reads like the names of potential lead characters in future success stories. Some were tried out on Tuesday night when United's Under-20s drew 0-0 with Motherwell at the Excelsior Stadium.

It speaks to a curious truth about youth coaching given Campbell has spent the past eight years working in the background at Tannadice - having first been employed by Craig Brewster, with whom he worked briefly at Inverness Caledonian Thistle - but his efforts can often be assessed in full view. Gauld and John Souttar have been his most conspicuous successes this season, joining a first-team squad already populated by youth-team graduates such as Keith Watson, Stuart Armstrong and David Goodwillie.

Campbell has been able to follow their progress more closely since Jackie McNamara has extended an invitation to join the coaching staff on matchdays, although the youth director is certain that it will not always be so easy to keep in touch with his young players. "Everybody knows that if [Gauld and Souttar] see out these contracts then we've probably failed," he says.

"They are the big names now, although I've never called wee Gauld 'big' in my life and Soapy [Souttar] played in front of 40,000 at Celtic Park at the weekend for the first time and looked like he was playing at St Andrews [United's training base]. We've had him since he was nine so you might say he is approaching his testimonial year. We are watching his progression with pride and excitement because, in my opinion, they are the hottest prospects in Scottish football."

Adopting the use of the plural in mid-sentence is not a coincidence as Campbell passes praise around. He also shares the successes of the youngsters with the younger age groups, even if some among them are already well aware of the details. "You might ask where the next John Souttar is coming from . . . well, we are playing his brother [Harry] in the under-20 team and he is just 14. He is literally the next Souttar," says Campbell.

That is also an indication of why United's youth system has proven to be so successful. Gauld and Souttar were used to playing with the big boys before they reached the senior squad, with the Tannadice club preferring to introduce players to a higher age group earlier than other clubs. The squad against Motherwell had an average age of just 17. It is an inexact science, since there will be players uncomfortable with such a step up, but the results have still been encouraging.

"That is maybe one thing we are doing [differently]," Campbell says. "I would say we are the youngest team in the 20s. That is something we have done all the way back to John Souttar, who played in the Youth Cup at the age of 15. The other thing is we have a young manager who is not afraid to throw them into the first team. There are not a lot of managers who would do that."