An A-level maths paper has been ditched at the last minute after it was accidentally sent to a number of schools in error.
The exam, due to be taken by students next Thursday, was delivered by the British Council to 43 schools in Egypt inside packets of past papers, according to Edexcel.
The exam board announced that it is withdrawing the paper due to concerns that it is no longer "secure" and a replacement will be used instead.
It admitted that as the paper has been replaced at short notice, there is a risk that a minority of students will end up sitting the original exam.
If this does happen, Edexcel insisted that all papers will be marked fairly.
An Edexcel spokesman said: "On Monday, we were made aware of a potential security breach relating to some of our exam papers.
"The British Council, which is responsible for administering Edexcel exams in Egypt, had accidentally sent a small number of live exam papers to schools, inside sealed packets of past exam papers.
"The British Council has taken immediate steps to locate and secure the papers as far as possible.
"For our biology and chemistry papers, we have reviewed the situation and are confident that the security risk has been contained.
"For our maths paper, due to be sat on Thursday 21st June, we have not been able to satisfy ourselves that the paper remains secure. For that reason, as a precautionary measure, we have decided to use a replacement paper, which we always have available for such situations."