THIS summer's Higher mathematics paper has been dumbed down, according to one of Scotland's most experienced exam setters.

Clive Chamber, a former principal examiner of maths for the Scottish Qualifications Authority (SQA), said the 2013 paper was easier than any previous paper he had seen.

The criticism has been backed up by a number of teachers, including the head of maths at a leading Glasgow private school.

The attack comes after the entire setting team for this year's maths Higher walked out after an internal dispute.

At the time, those who left warned the SQA would struggle to produce a quality paper because of the lack of expertise left at the exam body.

Mr Chamber, who oversaw the Higher between 1992 and 2009, said a typical exam should have 35% of questions deemed suitable for "A/B" candidates in order to separate the best-performing pupils from the rest, but he believes only 15% of questions in the paper reached the benchmark.

He added that candidates had been asked about the same area of the syllabus more than once, while one question was deemed more suitable for the lower level Standard Grade exam.

Mr Chamber said: "I thought it was a poor-quality paper and it was clear it had been dumbed down compared to previous years. This standard of paper just would not have been acceptable in previous years and there were not enough testing questions for the best candidates."

Mr Chamber also said it was "uneven", with the harder questions that were included scattered throughout rather than being placed at the end.

He said: "There should be a natural flow where candidates can work through the paper without panicking.

"It may be the case that, although the paper was easier than it should have been, some candidates will have struggled to finish because they got stuck on a question and were not able to pick up marks in subsequent questions because of a lack of time."

The view was backed by a number of teachers. The head of maths at a leading Glasgow private school, who asked not to be identified, said: "We were very disappointed with the paper. Rather than being a test of mathematical ability or skill it was a test of simple procedures."

Angus Mackay, principal teacher of maths at the Nicolson Institute, Stornoway, on the Isle of Lewis, said: "The paper was not as challenging as it should have been and we need to get back to the quality of papers we have had in recent years."

Marcus Barry, principal teacher of maths at Port Glasgow High School, Inverclyde, added: "It could not have been any easier."

The SQA said feedback from other teachers indicated the paper was fair.

Dr Gill Stewart, the body's director of qualifications development, said: "The exam paper is subject to a range of quality assurance checks prior to being signed off, including vetting and scrutiny by maths practitioners independent of those who set the paper.

"The fair and balanced nature of this year's Higher Maths paper has been backed up by the feedback SQA has received from teachers and schools."

The SQA said markers would complete a report to identify if there were any problematic questions – either too easy or too hard. This would be reflected in where the pass mark was set.

Ms Stewart added: "SQA uses all of this data to inform where it sets the grade boundaries. If the exam has been harder than planned, grade boundaries are adjusted down. If it was easier than previous years, grade boundaries are adjusted up."

The origins of the dispute can be traced back to last year's exam when there was tension between the setting team and SQA officials. The principal assessor had his contract terminated and the rest of the setting team walked out over the way he had been treated.