What the authorities say
The QCA: "The system rests ultimately on the professionalism and integrity of teachers and we have no reason to doubt that.
"Genuine concerns about the quality of coursework marking in specific instances should be reported to the awarding body. If concerns persist, people may contact us directly and we will investigate immediately."
Exam board Edexcel: "Exam moderators assess a sample of coursework from each teacher. If irregularities are found action can be taken, including disqualifying pupils' coursework marks. A lot of the system depends on trust. If the teacher has allowed a second, a third or a fourth redraft, that's wrong. If there's evidence of that, we can take very strong action."