A powerful group of MPs has called for urgent action over severe educational failings among Protestant children in deprived areas of Belfast.
The House of Commons Public Accounts Committee (PAC) also registered deep concern about poor basic Maths and English skills among pupils in both communities in Northern Ireland.
It alleged that a flawed Government approach "appears to set up a significant number of children for failure".
In a shocking report, the PAC highlighted a series of findings from its investigation into numeracy and literacy initiatives.
- "Disturbing differences" in achievement between pupils of different religious backgrounds in disadvantaged parts of Belfast
- Only 4.4% of children who entered GCSE Maths in mainly Protestant state secondary schools in these deprived areas achieved grades between A* and C2. The MPs described this statistic as "appalling"
- Only 17.3% of pupils in these same Belfast secondary schools achieved A*-C2 grades in GCSE English
- Nearly a quarter of P7 children here - around 2,000 girls and 3,000 boys - left primary school in 2004/05 with literacy skills below the standard level
- At Key Stage 3 in secondary schools - 11-14-year-olds - almost 7,000 of the pupils tested - 41% - failed to reach the standards expected of their age
- Girls are continuing to out-perform boys in Ulster schools, and the gap is "alarmingly wide" in Belfast.
The PAC called on the Department of Education to address the problems it had examined.
It said a strategy on numeracy and literacy launched in 1998 had failed to narrow the "long standing gap" between the best and lowest achievers, despite the expenditure of £40m.
The MPs also rapped officials for having altered targets on numeracy and literacy levels after they were not reached.
They further stated: "The department cannot continue with an approach to literacy and numeracy that, despite good intentions, appears to set up a significant number of children for failure."
Commenting on the report, PAC chairman Edward Leigh MP said: "Children only get one chance at a good education.
"While the committee recognises the achievements of many children in Northern Ireland which compare very favourably with the brightest in the rest of the United Kingdom, the school system in Northern Ireland has tolerated, for too long, a situation where a significant proportion of children are underachieving and leaving school without basic skills in literacy and numeracy."
The Tory MP added: "The excuses for this long tail of underachievement do not stand up to scrutiny.
"Since the introduction of the Department of Education's strategy for the promotion of literacy and numeracy in 1998, it has invested £40m on specific programmes, in addition to normal spending on the school curriculum.
"However, the strategy has failed to address this pattern of underachievement, depriving many children of future prospects and opportunities," he added.
The report contrasted education statistics for Belfast and Glasgow.
It said there was a reasonable degree of consistency between the performance of Catholic and non-denominational schools in Glasgow, but this was " certainly not the case" in Belfast.
"Here, schools with 40% or more pupils entitled to free school meals do disturbingly less well than their Catholic counterparts, as well as much less well than their counterparts in Glasgow," the MPs stated.
"Differences in performance by pupils from different religious backgrounds is a sensitive topic but we suggest that if real improvements are to be made the issues involved must be addressed.
"This requires thorough research and rigorous analysis so that evidenced-based actions can be put in place to overcome the difficulties.
"In its response to our report, we would like the department to explain in detail how it is tackling this issue which must be one of the major challenges Northern Ireland faces."