Ofqual has announced it is looking into the alleged leak of an Edexcel maths A-level paper taken today.
In a statement published on its website today, the exam watchdog said: "We are aware of the allegations of malpractice or wrongdoing in relation to Edexcel’s C4 maths paper taken today [23 June].
"We are working with Pearson to establish the facts and any action that may need to be taken to ensure that the examinations are fair and that standards are maintained. If anyone has information relevant to these allegations we would urge them to contact Pearson or us in confidence."
A spokeswoman for Pearson, which owns Edexcel, said: "We are continuing to investigate the allegations of exam malpractice, which we take extremely seriously. In the event that we find a breach we have systems in place to identify any unusual spikes or patterns in exam results and to mark accordingly.
"If a breach is confirmed then we will ensure that all students are marked fairly based on their performance in the exam. If anybody has information they would like to share with us in confidence they can contact us at firstname.lastname@example.org".
In the past 48 hours, pupils took to social media alleging the C4 paper had been leaked.
Earlier this week Edexcel announced that it was investigating the alleged leak of questions from the economics A-level paper taken on 19 June.