Research by the UCL Institute of Education found that pupils from Catholic and Church of England families did well because of their upbringing, not because of their school.
At best, researchers found, attending a religious school was associated with better results at O-Level, but did not affect how well the pupils did at A-Level or university.
For a cohort born in 1970 they analysed pupils' religious upbringing and the school they went to and found that while Christian pupils at Church of England and Catholic schools did better, this became statistically insignificant when the positive impact of their religious upbringing was factored in.
Part of the analysis found that students at Anglican and Catholic schools had approximately 1.3 times better odds of getting any A levels, but the faith the student was raised in was a more important predictor of how they were likely to do.
Studies have found that children at faith schools tend to get better exam results, but critics have argued that this is because they educate fewer children with special needs or from poorer backgrounds.
Professor Alice Sullivan, the study’s lead author, said: "Pupils who were raised in religious homes were more likely to succeed academically than those from non-religious backgrounds, whether they went to faith schools or not, and any small academic advantage that could be due to faith schools themselves was short lived.
The paper suggests that stricter parenting, the protective influence of being part of a faith community, or for Catholics, being of Irish immigrant heritage, could be behind the advantage.
Posted by Amanda Hopkins
Extract from www.telegraph.co.uk