The principal of St Andrews University has raised fresh doubts about the value of Higher qualifications, claiming they are not hard enough.

Dr Brian Lang has said admissions officers are struggling to identify the brightest pupils because so many are now achieving A grades.

As a result, Lang believes that the exams should be more difficult and a new grading scheme introduced to single out the most gifted youngsters.

The intervention of the head of Scotland’s oldest university will embarrass the Scottish Qualifications Authority (SQA), which has faced accusations that Higher exams have been “dumbed down”.

The proportion of pupils achieving A grades in their Higher exams has risen from 21% in 2004 to 24% this year.

Lang, who retires in December, said it was time for the system to be overhauled. In England, an A* grade is to be introduced to A-levels from 2010. The exams will feature new questions designed to stretch the most able students. Pupils who answer them correctly will receive the new top grade.

“I would like to see Highers and A-levels made harder,” said Lang. “We have so many applicants wanting to come to St Andrews who have five Highers at A or three or four A-levels at A.

“The problem we have is differentiating at the top end. I’m not saying the exams are easy. But if they were difficult, this would let the stars shine.”

Murdo Fraser, deputy leader of the Scottish Conservatives, said he supported Lang’s call for a review. “At St Andrews, which has a lot of straight-A students applying for places, it would be helpful to differentiate between people of different academic ability,” he said.

A SQA spokesman said the proportion of Highers passed at A grade has remained broadly constant. “The Higher remains the gold standard of Scottish education and continues to provide a broad-based, rigorous test of students’ abilities,” he added.

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