In education, they call it the pupil-teacher ratio and it dictates how much attention each child can receive. The problem for Gordon Strachan is that Celtic’s burgeoning class size may spread his precious coaching time too thinly. He must also hope that some of the underachievers do not start to heckle him from the back of the class.

Celtic used 20 players against Basel on Thursday but still Artur Boruc, Shunsuke Nakamura, Evander Sno, Paul Hartley, Gary Caldwell, Chris Killen, and Darren O’Dea were missing. Jose Mourinho believes the optimum size for a squad is 23, so Celtic could probably do with shedding a few before the transfer window closes at the end of August.

It is not too difficult to spot those they would like to leave. Some of Thomas Gravesen’s manic performances since signing from Real Madrid have been of the headless chicken variety, although beheaded poultry might deem the comparison harsh. Jiri Jarosik, in contrast, shows much more economy in his effort, a little too much perhaps, and has already said he would like to leave. There are also too many strikers and centre-backs for Strachan to keep happy. With Stephen McManus and Jan Vennegoor of Hesselink established in these positions, the question is who will partner them.

The manager, though, believes his squad will police themselves when it comes to keeping the inevitable gripes in-house. “If you watch the players’ reactions to team selections last year, I thought it was absolutely phenomenal. Look at the Cup final and either BBC or ITV quizzing Kenny Miller about his future and he was brilliant for his teammates. The headline was Kenny Miller hints he might be unsettled. That’s not bad when he ‘hints’ he could be unsettled. So the players themselves look after each other fantastically well. That’s the reason we won the league last year. We were the best squad.”

If you were to imagine a mischief maker at the back of Celtic’s class it might be Derek Riordan, who went to the same school in Edinburgh as his manager. Last season, Riordan became something of a cause celebre with the Celtic support and his replacement by Miller in the Scottish Cup semi-final saw a significant section of it boo the change. Riordan later complained bitterly about his omission for the final. “I never really got a chance last season, I thought I did all right in the games I played in but we’ll see how it turns out this season. The cup final and not getting on was the big one. I’d played and scored the week before. That was the most disappointing thing.”

As he speaks, Strachan appears at his back but there is nothing being said that you suspect has not already been discussed by them. “He doesn’t have to convince me he’s a good player, I signed him. Anybody here who has a talent, it’s up to them to enhance it as there’s people here who are very good at their jobs and the hungrier ones will always be more successful. That’s not about Deek, that’s about anybody who joins this club.”