Concern about the lack of suitably qualified candidates applying to become headteachers in Scotland has been growing over recent years as large numbers of heads are reaching retirement age.

That has now been compounded by proposals to introduce a new compulsory leadership qualification for all applicants for headships. There is consensus that the best headteachers are inspirational leaders who motivate staff and pupils so that learning and teaching take place in a positive atmosphere. Leadership by the head, through personality and example, is the key to a successful school.

This is recognised by the unions representing headteachers in Scotland. At both primary and secondary level, they support training to enhance the capabilities of future heads.

Ken Cunningham, general secretary of the School Leaders Scotland, which represents secondary heads, however, warns that education authorities are already "struggling to get good people in posts". His concern is that too rigid a qualification will deter people from applying. The main difficulty with the new, compulsory qualification is the timescale. Although the cut-off point for every candidate to comply is in five years' time, the worry is that too few will have trained to ensure there is competition for every post.

Given the long-anticipated crisis in schools due to the large number of imminent retirements and the reports from current heads that teachers with potential to become leaders are not applying because of very difficult working conditions, it is essential that the new system should enlarge not reduce the pool of future headteachers.

Council cuts are taking their toll across public services. One of the difficulties of large-scale reduction in the number of principal teachers and depute heads, however, is that it is from this group that future heads are drawn. There may be grounds to re-examine this, particularly because principal teachers also have an important role as mentor to younger colleagues. Learning from the example of others can be leadership training by another name.

Training is to be encouraged but eligibility should not be determined by paper qualifications alone. All teachers have made considerable efforts to adapt to the Curriculum for Excellence. Morale must not be undermined by additional burdens on those with the talent to take on headships. We cannot afford to lose their skills and commitment because the quality of Scottish education is to a large extent determined by the calibre of its headteachers.