The report found two in five pupils leave school without the required literacy and numeracy skills.

Unacceptably large numbers of pupils are failing to achieve even minimal levels in literacy and numeracy, an independent report has concluded.

The Northern Ireland Audit Office has examined levels of attainment in maths, reading and writing at primary and secondary schools in Northern Ireland.

It found that two in every five of those who leave school after their GCSE exams were failing to achieve the required minimum standards of five A*-C passes.

It said girls fared better than boys.

The NIAO report also found a "strong correlation between between low levels of academic achievement and free school meal entitlement (an indicator of social deprivation)".

It said that only 32% of pupils entitled to free school meals in 2010-11 achieved five GCSE passes at grade C or above,

This compared with a rate of 65% among pupils who were not entitled to free school meals.

The report also concluded that "social deprivation appears to have a greater negative impact on achievement levels in controlled (mainly Protestant) schools than in their maintained (mainly Catholic) counterparts".

The head of the NIAO, Comptroller and Auditor General Kieran Donnelly, said: It is vital that our education system does all it can to address underachievement in order to improve the life chances of our young people and to ensure that our economy is well equipped to compete in an increasingly global marketplace."