SCOTTISH pupils who sat a controversial new maths exam were less likely to secure a top grade, according to new figures.

Scotland's exam body pledged no-one who sat maths Highers this summer would be disadvantaged after many left exam halls in tears.

However, official figures released as thousands of Scottish pupils receive their exam results show lower numbers securing an A or B grade who sat the new Higher compared to the existing Higher, which was run in tandem.

James Reid, a former principal assessor of mathematics with the Scottish Qualifications Authority (SQA) between 2000 and 2012 described the difference in pass rates between the two exams as "substantial".

He said: "Given that roughly the same number of candidate sat both papers and that these are from the same cohort of pupils I would have expected a much closer correlation.

"It means that, in my opinion, pupils would have a better chance of achieving a top grade sitting the old Higher rather than the new Higher and that is completely unacceptable in an exam system.

"It is worrying to see such a huge difference in pass rates. The SQA said no candidate would suffer as a result of these exams and quite clearly candidates who have sat the new Higher have suffered."

However, Angela Constance, the Education Secretary, said it was not possible to make direct comparisons between existing and new Highers.

She said: "For one thing you have got two different cohorts of young people sitting those exams and in terms of the new Higher you will have a greater proportion of S5 pupils sitting that.

"It is also important to recognise that the SQA has well-established processes that kick in every year for every subject that test the performance of the exam and ensure that standards are maintained and that no young people is unfairly treated."

A spokesman for the SQA admitted the new Higher was more difficult than intended, but said comparisons between new and existing qualifications were "complex".

He said: "In setting the grade boundaries for existing and new Higher mathematics we looked closely at a range of factors including the routes taken into the qualification, the proportion of entries from S5, S6 and college, and the performance of candidates in areas of the assessment that were common across both qualifications.

"We also took into account the overall level of difficulty, ensuring we applied the same standards for both qualifications.

"After reviewing the new Higher Maths exam, it was clear that the assessment distinguished between all areas of ability, but that, overall, the paper was more demanding than intended. The results show the full spectrum of ability including some candidates who performed very well."

The figures from the SQA show one in five of the 10,220 candidates who sat the new paper achieved an A grade with 44 per cent achieving either an A or a B.

In contrast, one quarter of the 10,854 pupils who sat the existing maths Higher paper achieved an A grade and 50 per cent achieved either an A or a B. The overall pass rate was 71 per cent compared to 73 per cent.

Earlier this year the Scottish Government faced calls for an urgent review of Higher maths amid claims papers were "flawed and too difficult".

Labour’s Iain Gray wrote to Ms Constance, citing the "exceptional circumstances" and First Minister Nicola Sturgeon also came under fire from opposition leaders.

Following the exam, two internet petitions were started to highlight the problems with both exams with one stating: "Students, teachers and parents alike are in disbelief at the exam set by the SQA for Higher maths. It bore no resemblance to the course studied and specimen papers provided."