Police investigating the leak of an A-level maths paper on 13 June have arrested two people, the exam board, Edexcel, has said.
Two questions from the paper were posted on Twitter the day before the exam.
In the now deleted post, the account holder urged students to get in touch, offering the full paper for £70.
Pearson Edexcel said: “We understand students are rightfully concerned and want a fair playing field.”
The parent company’s senior vice-president in charge of schools, Sharon Hague, added: “Our key priority is ensuring no students are disadvantaged in any way.”
The Metropolitan Police has confirmed it is leading the investigation into the leak and will issue a statement shortly.
Earlier this year, Pearson said it would be trialling a scheme where microchips were placed in exam packs to track the date, time and location of the bundles.