The funding gap between schools in Wales and England will grow to an all-time high when new figures are released later this month, an education expert has predicted.
Research by David Reynolds, professor of education at Plymouth University, last year revealed that the gap between the two nations had grown to 9.7 per cent since devolution, or pound;496 per pupil in the average secondary school.
Speaking to TES Cymru, Professor Reynolds said the spending difference is now likely to be above 10 per cent, and predicted that the per-pupil gap lies somewhere between pound;500 and pound;550.
His prediction comes following the appointment of new First Minister Carwyn Jones, who made a campaign pledge to close the funding divide. That will now prove to be a "very difficult task", Professor Reynolds said.
His initial research, revealed in TES Cymru last November, was dismissed by the Assembly government, which attacked Professor Reynolds for "running Wales down" - but earlier this year its own statistics confirmed his findings.
Professor Reynolds said he was "delighted" with Mr Jones's pledge to increase school spending by at least 1 per cent above the block grant Wales receives from Westminster.
"This is the very first time that anybody in Welsh politics has acknowledged the gap exists," he said.
"I regard it as a real affirmation of the work I did with TES Cymru last year."
He warned ministers that they must "claw back" cash from other government departments. Investment in health, central government employment and culture, media and sport had grown rapidly, he added.
"These are expenditure areas that have grown fat on the cash that should have been spent on education.
"Getting money back from these areas will prove difficult. Health has been the big winner in the recent budget, and one of the great successes of devolution has been in the area of culture and language."
The government must also tackle local authorities which hold back funding earmarked for schools, Professor Reynolds said.
Figures released earlier this year showed councils in Wales were holding back more cash than ever before, with plans to delegate just 75.7 per cent of their education budgets to schools in 2009-10 - down from 81 per cent in 2002-03. The rest of the cash - a record pound;579.3 million - will be held centrally.
An Assembly government spokeswoman said: "It would be inappropriate to comment on statistics that have yet to be published.
"The First Minister has made a significant commitment to increase spending by 1 per cent above the block grant we receive from the UK Government from the 2011-12 financial year.
"The Education Minister has supported this pledge and emphasised the importance of clear decision-making as a priority in his new role."