It is Friday evening and in a church hall in Hamilton, South Lanarkshire, a mixed group of teenagers is arriving for a dance class.
As they emerge from the changing room in leotards, the teacher vets their appearance. Girls with their hair in fashionable loose strands are told to pin it all back; one wearing a T-shirt is told to take it off.
Protest is met with a warning that if she doesn't, she might as well go home. This obviously isn't your average after-school session.
The warm-up alone for the jazz-dance class is enough to make you gasp for breath. Slickly choreographed to pounding music, the dancers work through a variety of exercises. They require no prompting; their teacher merely wanders among them, admonishing some to work harder, lift a leg higher.
The display brings to mind the backing dancers of a pop act or a West End musical, far more polished than an average dance class.
That is hardly surprising: the students on the Jazz Art UK programme at the Lanarkshire-based Scottish School of Musical Theatre spend an average of 10 hours a week honing their skills. They have classes in the evenings after a normal school day, at weekends and during the school holidays. It is a big commitment, but many of them are heading ultimately for a career in performance.
To facilitate this, the school puts forward students for Royal Academy of Dance examinations. In addition, it now enters some for the relatively new Higher qualification in dance practice.
In its first year - 2002 - 10 students from two institutions took the exam; the figure grew to 78 last year (48 failed) and 156 this year.
Candidates have to demonstrate competence in four dance techniques, from a list that includes ballet, jazz, contemporary and Scottish country dancing.
Each candidate then chooses two to perform for an external moderator. In addition, they create their own choreography, planning it, teaching dancers and presenting the finished piece. Finally, in the written component, completed under exam conditions, they evaluate critically their choreography and the self-made technical improvement plans they have been working on throughout the year.
This is the second year that Jazz Art UK students have taken the exam. Last year, two of the six students who were entered received the only A passes to be awarded, one by the youngest student in Scotland to pass, at the age of 13. In recognition, the Scottish School of Musical Theatre has been named a unique centre by the SQA.
"The difference between this and other institutions that prepare for the exam is that our students are performing at the very top level of the Higher. You simply cannot compare them with other entrants," says the school's educational consultant, Ann McEwan.
Ms McEwan and Sheridan Nicol, the school's artistic director, agree the Higher is useful for aspiring dancers. Not only is it recognised by the London School of Contemporary Dance and the London Studio Centre, it has the same weight as any other Higher for university or college entry.
Since many of the Jazz Art UK students take it at 14, Mr Nicol is keen for an Advanced Higher. "At the moment there are some units that you can teach, but you can't get an overall award," he says. "It's frustrating because we definitely have students who could do it."