Latest info from the exam board:
qualifications.pearson.com/en/news-policy/qualifications/a-levels/maths/a-level-maths-update-17-june-2019.html
They’ve found where the leak came from and police are involved. They’ll use statistical analysis of performance on previous papers to identify students who benefited from the leak, and will possibly disqualify them.
Potentially the blacked out questions that were available will be discounted from the exam.
I read on twitter that the paper was shared around some independent schools - these will be looked at closely.