Students have been voicing their concerns after part of an A-level maths paper was leaked online.
Sections of the A-level Maths Paper 3 exam were shared online ahead of students sitting the exam on Friday.
Those affected have suggested it was leaked "around 12 hours prior to the exam on several social media forums".
The Edexcel exam board has launched an investigation.
Students have been speaking to the BBC about their frustration and disappointment over the leak.
Harry, 18, Oxfordshire
"I am an A-level student, hoping to go to the university of Bath to do computer science in September, a course that requires an A in maths to qualify. Sadly I feel that, after this week, those hopes have been crushed.
"The leak on such a wide scale; there is no way you can prove who has been advantaged or disadvantaged.
"For someone like me, who struggles with Statistics and Mechanics, I felt so happy coming out of that exam - thinking I had nailed 70-75%, which is a very good mark compared to ones I was getting previously. Then I checked my Twitter and saw that the exam was leaked. My heart sank.
"I cried in the car on the way home because I knew that my hard work and effort - staying up until 1am revising for this exam - is now worthless, as some idiots have skewed the grade boundaries for all of us.
"This was incompetence from Edexcel and they are trying to protect themselves from any blame, saying it was the some of the [exam] centres' fault. It may be true, however, they are failing to grasp the magnitude of the leak and continue to deflect blame away from themselves.
"This year has been a shambles from Edexcel. The first two papers were far too difficult - but the leak is just a step too far. We need retribution for those late nights and all that hard work we put in, because we shouldn't be disadvantaged if we're honest people.
"I feel that the only way we can solve this is to give predicted grades to every student who took the exam, as there is no way you can prove who is guilty and who is not."
Scarlett, 18, Nottinghamshire
"Many of us who sat the exam only later discovered that the entire exam script had been leaked beforehand.
"Edexcel had been made aware of this before the examination took place, yet did not issue the contingency paper and instead allowed us to sit the exam.
"I came out of the exam at 3pm and looked on Twitter to see what other people thought about the exam. Then I saw it was leaked. I spoke to the head of my sixth form but she didn't know what will happen.
"I was mortified and I still am. Many students, like myself, who have revised for two years for these exams now feel betrayed, and will suffer as a result of Edexcel's failings. Those who have cheated will cause the grade boundaries to rise, leading to further injustice.
"The exam board have suggested that the exposure of the leaked script was 'very limited'. There is no way that Edexcel can know this, due to the very nature of social media.
"There is, in fact, reason to believe quite the opposite: that the papers were leaked to thousands of students.
"I think it's unfair. I would like Edexcel to accept the gravity of the situation and acknowledge that this has happened for three years running.
"In the meantime, we anxiously await their actions, which will ultimately dictate our future."
Ben, 18, Wiltshire
"I am extremely frustrated by the situation. The whole exam season from Edexcel has been really poor, with questions requiring content not on the syllabus, a past exam question from 2014 copied and pasted into Paper 2 and the whole of Paper 3 being leaked before the exam.
"Edexcel's statement offers no reassurance to students that the situation will be resolved. They claim it was leaked in a "very limited way, shortly before the exam". However the paper was leaked around 12 hours prior to the exam on several social media forums.
"With the ability to send the paper to hundreds of people within minutes, the scale of this leak could potentially be huge and it is almost impossible to track.
"As well as this, 12 hours is plenty of time for students to do the paper and compare answers.
"Edexcel have stated they have 'processes' in place and yet give us no indication as to what they are. As students we have the right to know how they intend to make the paper fair, especially if they cannot identify who had access to it beforehand.
"They have stated that they will hold the individual leaker responsible for their actions. However, scape-goating one individual or one centre does not solve the problem [given] that so many people have had access to the paper.
"In terms of solutions, I cannot foresee one that will keep everyone happy. By lowering the grade boundaries, you give the cheaters what they wanted anyway; by discounting the paper, you disadvantage people who were relying on it to bump up their grade; by giving people their target grades, you are taking away from individuals who have worked extremely hard to get a higher grade than their target.
"I believe this has been very poorly handled, and the fact that the paper has been leaked for the third year in a row is disgraceful.
"For an exam board, surely their primary objectives should be to give their students a fair and honest representation of the course and to keep the paper from being leaked. This year, Edexcel have failed drastically on both fronts."
"It could have a life-changing knock-on effect on students who have worked tirelessly for two years trying to get grades they require to go to university.
Interviews by Andree Massiah, UGC Hub, BBC News