Questions from today’s A-Level exam leaked online before the test.
Two exam questions from Edexcel’s maths paper 3 appeared on Twitter last night.
Pearson, the firm which operates the board, has launched an investigation.
The board has also seen two petitions launched this week complaining about the difficulty of other A-level maths papers.
The Student Room website has images of the tweets in question.
Tweets accompanying the images reportedly offered the whole paper for sale for £70.
In a statement Pearson said: “We are aware that an individual circulated blacked out images of two exam questions on social media ahead of today’s A-level maths exam.
“We are investigating the source of this.
“All students should be reassured we have well-established processes in place to ensure no-one will be advantaged or disadvantaged, and this paper will not have to be resat.”
Edexcel A-level maths papers were also leaked in 2017 and 2018.
In April, Pearson announced it had made progress in their investigations into both cases.
Thousands of pupils who sat A-level maths papers on June 5 and 12 have signed an online petition calling for “extremely difficult and unreasonable” papers to be marked with special consideration.
Almost 11,000 pupils have signed a Change.org petition regarding Edexcel’s Pure Mathematics A Level, which calls for the exam to be marked fairly “in order to give us a chance at our future”.
A further petition against the exams on Change.org by Kamil Zelechowski gained almost 3,000 signatures. The petition says students’ hopes of gaining university places had been “shattered”.