A Catholic grammar school was responsible for a “serious security breach” of post-primary entrance papers sat by primary seven children, a Department of Education independent investigation found.

Education Minister John O’Dowd said yesterday: “The investigation concluded that, while there had been a breach of post-test security, there was no evidence that any child had either been advantaged or disadvantaged by this breach.

“The investigation concluded, however, that the potential for a serious breach had been demonstrated and still exists.”

It is understood the school at the centre of the scandal, which has not been named, photocopied the 2009 GL Assessment English and maths papers, later used as a practice paper to prepare some children for the 2010 transfer test.

Copying the papers was in contravention of the school’s contractual agreement with the English-based GL, which is responsible for the tests’ content.