That is the warning from a new report by the think tank Onward, which compared the performance of Welsh students to international benchmarks.
The report, titled Devolved to Fail, paints a stark picture of long-term educational decline in Wales, drawing on the latest OECD Programme for International Student Assessment (PISA) scores and projections through to 2040.
In the most recent PISA results, Welsh pupils scored 30 points lower than their peers in England in both reading and science, and 26 points lower in maths—equivalent to a full year of lost learning.
Ellie Craven, senior researcher and author of the report, said: “Wales has the lowest education outcomes in the UK – and the gap is set to grow.
“This is not inevitable.
“But without urgent reform, Welsh pupils will be left behind their peers not just across the UK, but globally.”
The report finds that the average pupil in Wales now performs at the same level as England’s most disadvantaged students.
If current trends continue, Wales could fall below Romania in international rankings by 2040.
Onward attributes the decline to several factors, including the continued use of outdated literacy methods, a national curriculum it describes as “overly vague,” and weak school accountability following the abolition of league tables.
School absence rates in Wales are 70 per cent higher than in England, with 12 per cent of pupils regularly missing school compared to 7.1 per cent in England.
The report notes that more than a third of Welsh students miss at least 10 per cent of lessons.
Estyn, the Welsh schools inspectorate, found that two-thirds of secondary schools need to improve self-evaluation, and half had unsatisfactory teaching or attendance.
Last year, only half of secondary schools inspected were rated satisfactory for teaching or attendance.
The report recommends three urgent reforms: converting failing schools into academies and reintroducing league tables; replacing the current skills-based curriculum with a “knowledge-rich” model that mandates phonics-based reading instruction; and swiftly implementing Estyn’s attendance improvement recommendations.
Sir Simon Clarke, director of Onward, said: “Children in Wales are being let down terribly by a system that avoids accountability and clings to failed methods.
“There is no reason Welsh children should achieve less than their peers elsewhere in the UK – but that will remain the case unless the Welsh Government is brave enough to deliver change, or is itself changed at next year’s elections to bring about new leadership.”
The Welsh Government has disputed the findings.
A spokesperson said: “We don’t recognise these claims.
“Our recent GCSE and A-level results show improvements in attainment and record results in the top grades, and data from personalised assessments show progress at primary stage learners.
“Wales’ education system is moving in the right direction thanks to the additional support we are providing to schools, continued investment and the hard work of school staff.
“We will continue working hard to raise education standards for all.”
Onward’s report also raises concerns about the long-term impact of current trends, warning that without intervention, Welsh students will continue to fall behind both nationally and internationally.