EXAM officials have been forced to admit mistakes were made in a national computing science exam sat by thousands of pupils as calls mount for a review.

The Scottish Qualifications Authority (SQA) said a "small number" of typographical errors were included in the National 5 exam sat on May 27th.

The SQA previously insisted there was nothing wrong with the paper and said feedback from teachers had been positive.

Read more: Teachers attack 'disgraceful' computing science exam that was 'riddled with errors'

The admission came after computing science specialists launched an outspoken attack on the qualification highlighting problems with 19 out of the 21 questions.

Teachers described the paper as one of the worst ever set and called for the SQA to hold an immediate inquiry.

Typographical errors included a question that read: "Give one reason of using this type of selection" while in another question the weight of a tablet computer was given as 65kg.

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Critics also highlighted confusing questions, questions with multiple possible answers and some where knowledge would have been required from outside the course such as the legislation around cloning of phones.

Kate Farrell, executive committee member of Computing at School Scotland, a body that represents subject teachers, said members have highlighted a catalogue of errors ranging from grammatical mistakes to questions that could not be answered.

She said: "We are concerned this will have affected the performance and shaken the confidence of many candidates.

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"We understand writing an exam paper is a collaborative process, and one that involves teachers who write questions for the paper, but we are greatly concerned that the current method of writing exam papers does not include sufficient quality assurance leading to duplication and errors.

"We would encourage the SQA to carry out a review of its exam writing process to ensure these mistakes do not happen again and we urge it to ensure that robust processes are in place to ensure all assessments are error free."

Ross Greer, education spokesman for the Scottish Greens, backed the calls for an inquiry saying: "An investigation into what went wrong is absolutely essential. Students and teachers have clearly been let down.

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"How a paper which seems so thoroughly flawed could have made it through quality control processes and on to students’ desks raises serious concerns and I will be raising this issue with ministers as soon as possible."

A spokesman for the SQA said: “The National 5 computing science exam paper met our published course and assessment specifications. The paper did contain a small number of typographical errors."

The controversy comes at a difficult time for computing science in schools with falling teacher numbers and concern the importance of the subject to the future economy is being ignored.

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The concerns about the National 5 computing science paper came to light in a number of internet forums used by specialist teachers of the subject.

One teacher from a high profile Edinburgh private school described the paper as "the most error-strewn and, in places, incomprehensible examination I’ve seen in my career".

He said: "It contains typos, incorrect code and other errors which make questions unanswerable. It is strewn with grammatical errors, it requires knowledge which is not in the course and some questions are so poorly designed and worded that even the most able and best-prepared of candidates could well be defeated by them.

"There has clearly been insufficient quality assurance, as even the most cursory glance by an experienced computing science teacher would have picked up many of these errors. At best, the paper reads like a first draft; could the explanation be as simple as an incorrect version being published?

"At a time when computing science faces an existential threat in some parts of the country, colleagues and pupils need to be better served than this."

In 2014 it was revealed that the number of computing science teachers in Scotland has dropped sharply, sparking fears for the future of the subject.

New figures show teacher numbers in the subject have fallen by 109 in the past two years - a drop of 14 per cent. One in eight secondary schools in Scotland does not have a computing science specialist at all.