Harrogate Grammar School has apologised to pupils after entering them into the wrong Religious Studies GCSE paper this week.
218 Year 11 pupils will await the results of the GCSE short course knowing they were not fully prepared to answer all the questions on the paper.
A teacher submitted one digit incorrectly in a code when entering the pupils for the paper, so it was different to the one they expected to sit.
The paper was similar, but the question style was not what students were expecting, and meant they were limited in terms of the number of questions they could attempt.
Now, the school has contacted the exam board to ask for its students to receive consideration when the exams are graded.
Headteacher Richard Sheriff said: “We are disappointed to have let the students down in this way. We have done everything we can to contact the exam board to allow consideration for the students.
“We take this extremely seriously, but many students were not aware there was an error.”
In a statement, HGS explained: “The school would like to reassure parents and students that this mistake does not cast doubt on the integrity of our examination systems in general.
“Over many years and many thousands of examinations this has not occurred before and we will do all we can to ensure it does not happen again.”
A concerned parent, who did not want to be named said: “I find it hard to believe the school could do something like that.
“It is a mistake that should have been spotted.”