Tony Finn, the education convener of the General Teaching Council for Scotland, told the council meeting on Wednesday: “Schools in less attractive areas are finding it more difficult to get supply teachers, some subjects find it impossible and the problem affects the primary as well as the secondary sector.”

Mr Finn, head of St Andrews High in Kirkcaldy, said it was now even more important to ensure supply teachers get a quality experience in schools so they do not become dispirited and turn their backs on teaching.

The GTC might soon have to look at supply teachers’ training and the support they receive, Mr Finn added. He was responding to a research study from Aberdeen University by Jennifer Spratt, a supply teacher, which portrayed a “disappointing” picture of the way supply staff are treated. This had serious implications for the quality of learning and teaching, Mr Finn said.

Thestudy (TESS, October 20) concluded that, while there was a constant shortage of supply teachers, there was little on offer to such teachers to improve their performance. “The absence of training, of structured support and of open evaluation must have had implications for their classroom performance,” Ms Spratt said.

“While the supply teachers who were deemed to be competent from the outset could access informal mechanisms of support as they became well-known and respected, the supply teacher who needed a helping hand had nowhere to turn, and was likely to face repeated rejection.”

She found it “quite remarkable” that supply staff taught classes with barely any training.

The GTC has also signalled a related supply issue as it decides whether to approve additional teaching qualifications for the new subjects brought in by Higher Still. This week’s meeting approved a look at philosophy.

Douglas Weir, dean of the education faculty at Strathclyde University, warned that the teacher education institutions would not be able to offer these new qualifications without specific funding.

Neil Munro