One of the UK's biggest exam boards is to be fined £125,000 after partial solutions to GCSE computing tasks appeared in a textbook it endorsed.
A number of Northern Ireland pupils sit the GCSE computer science exam with OCR.
Exams regulator Ofqual announced it is imposing the penalty on OCR in a report that said the mistakes, which related to controlled assessment - a form of coursework completed under strict conditions - meant that some students had been given an "unfair advantage".
As well as errors relating to textbooks, the watchdog said there had been failures to refer suspected malpractice for investigation, and inconsistencies in advice to schools. OCR apologised for the issues, but insisted that they did not have an impact on students or exam results.
The watchdog's report said that in April 2016 it had been notified by the exam board that a textbook published four years earlier, that it had endorsed, appeared to contain the solution to parts of a controlled assessment task taken by students in 2016.
In its findings, Ofqual said the incidents appeared to have occurred because the textbook authors were the principal moderators for two units of the GCSE course, and in that capacity had been instructed to devise the 2016 and 2017 controlled assessment tasks for GCSE computing.
It noted that OCR has spent more than £300,000 addressing and resolving issues.
An OCR spokesman said: "We have invested heavily and worked extensively to put things right."