Helen Liddell was announcing the expected Government go-ahead for the relaxation of “age and stage restrictions”. These require the Scottish Qualifications Authority to give permission for pupils to sit a Standard grade exam in third year or a Higher in fourth year - on a subject-by-subject basis.

The change means that schools will now take the decision.

Mrs Liddell commented: “It is important that Scotland’s young people are challenged to reach their full potential. Our most able pupils must have greater opportunities to stretch their abilities. It is equally important that less able pupils will be able to obtain qualifications within the compulsory school stages.”

The teaching unions have in the past been wary of allowing the ablest pupils to progress on a “fast track” that might lead to premature selection of an elite group of learners.

Mrs Liddell said it was important for the most able to make rapid progress but said the new flexibility “will also make it easier for less able pupils to gain qualifications before leaving school”. The decision to leave it up to schools, and therefore teachers, to use their new discretion has reassured the unions.

The move follows consultations last year in which two-thirds of the 250 submissions showed a preference for a limited relaxation of the current restrictions. The change will apply to examinations from 2000 onwards.

The consultation also overwhelmingly endorsed the view that the normal experience for third and fourth-year pupils should be the two-year Standard grade course.

But relaxing the rules has become inevitable with the advent of Higher Still, which has opened up the option of pupils sitting Standard grades at Credit level in third year.

The Government’s task force on underachievement in 1996 also suggested that Higher Still units at Intermediate I and II could replace Standard grade Foundation and General courses for less academic pupils.