Hundreds of pupils in Northern Ireland studying a new computer science GCSE may have their coursework marks cancelled after details were leaked online.
The decision has been taken by exams regulator Ofqual.
It will only affect those pupils sitting the GCSE through UK exam boards AQA, OCR, Pearson and Eduqas.
The non-exam assessment is worth 20% of the total mark for GCSE computer science.
Pupils sitting ICT or digital technology GCSEs through the Council for Curriculum, Examinations or Assessment (CCEA) are not affected.
The exams regulator Ofqual said it plans to make that mark void as solutions to the coursework programming tasks had been seen by thousands of pupils online.
Ofqual said the non-exam assessment may have been leaked by teachers as well as students who had completed the task.
There is no suggestion that any of the leaks came specifically from Northern Ireland.
The breach affects year 11 and year 12 students.
The latter are due to sit their exam in the subject in summer 2018.
The Joint Council for Qualifications (JCQ), which represents the exam boards, said that it was not possible to specify exactly how many pupils in Northern Ireland were affected, “as schools have not entered all candidates for the summer 2018 examinations.”
However, it said that last year, 630 pupils here sat computing qualifications with exam boards other than CCEA.
A statement from Ofqual said: “Non-exam assessment in computer science is intended to test students’ programming skills and is worth 20% of the overall nine to one grade.
“However, there is evidence that some of this year’s tasks have been posted to online forums and collaborative programming sites, contrary to exam board rules.
“Detailed solutions have been provided in many cases, and some of these posts have been viewed thousands of times.
“The apparent extent of malpractice in this qualification leads us to believe that it is no longer possible for exam boards to ensure that grades awarded next summer will fairly reflect the ability of all students unless changes are made to the assessment arrangements.”
Ofqual is now running a consultation on what alternatives to put in place.
However, it said its preferred option would be to keep the non-exam task but for it not to count towards the GCSE overall mark.
Julie Swan, executive director for general qualifications, said: “It is with great reluctance that we are proposing to change a qualification for which students are already studying.
“However, we must take immediate action to address these issues and the potential impact on public confidence in relation to this qualification.
“Subject to the consultation responses, we believe our preferred solution will deliver fairer and more reliable results than would otherwise be the case.”