A Jewish secondary school has been criticised for hiding questions in an exam paper because they were at odds with its beliefs.
The OCR exam board, which investigated claims that pupils at the Yesodey Hatorah Senior Girls School in north London were being prevented from answering certain questions in their obscuring questions in a GCSE science paper, said the action was "not good exam practice".
But it added that its inquiry concluded that no student gained an advantage by the school's actions, and it did not penalise any candidate.
It is understood that following the investigation, OCR, other exam bodies, the Department for Education and the schools inspectorate are looking to see whether there should be clearer guidelines for faith schools on how to deal with a situation where they are faced with questions in exam papers that are at odds with their belief system.
The matter was referred to the exam board - one of the biggest in England - by the National Secular Society (NSS) earlier this month.
The NSS raised concerns that teachers at the school had been "blacking out aspects of question papers" and asked for an investigation.
It is thought that the obscured questions may have related to an issue at odds with the school's religious beliefs.
Yesodey Hatorah school, which is rated outstanding by Ofsted, serves the Orthodox Jewish Charedi community in Stamford Hill, north London. Members of the community do not have access to television or other media, such as the internet, and aim to live modest lives governed by the Torah.
No one at the school was available for comment.
An OCR spokesman said: "Ensuring the integrity of the exam system is of paramount importance to OCR and we will always take all the steps necessary to protect it. On this occasion we conducted a thorough investigation into the centre concerned and found that no candidate gained an advantage. As a result, we did not penalise any candidate.
"We have tried to respect the religious and cultural sensitivities of this community whilst protecting the integrity of our exams. That said, we do not consider obscuring aspects of question papers to be good exam practice.
"We are raising the matter with the Department for Education and Ofsted as well as our fellow awarding bodies, through the Joint Council for Qualifications. We are also in the process of agreeing safeguards with the centre to ensure good exam practice in the context of today's pluralistic society. Ofqual are also fully aware of our investigation and its outcome."
An NSS spokesman said: "Pupils being denied the right to answer exam questions by teachers pushing their own religious agenda is shocking enough. However, the wall of silence surrounding this incident reveals the extent to which not upsetting 'religious sensitivities' is now deemed more important than a young person's right to a rounded education.
"This is an extreme example of a common problem throughout our state education system: children's education being compromised by the influence of religious organisations.
"The time has come to draw a line under this faith schools experiment and separate the realms of religion and state education. Schools should be about learning how to think, not what to think."