Research commissioned by TES Cymru that revealed significant underinvestment in education compared with the rest of the UK will be used as evidence in a major inquiry into child budgeting starting next week.
The Assembly government's children and young people's committee will investigate whether children are being short-changed in schools and other publicly funded services during the inquiry, which is expected to last until Easter.
Last November, TES Cymru revealed Wales has spent 6.4 per cent less on education than the UK average since 2002-03. It was also estimated that schools in England now have Pounds 500 more per pupil in their budgets than schools in Wales.
David Reynolds, who conducted the research, will be the first to give evidence to the inquiry.
The professor of education at Plymouth University caused controversy by saying children's futures were being blighted by a lack of funding in schools. The academic was criticised by the Assembly government for attacking Wales.
Writing in TES Cymru today, Professor Reynolds says schools in Wales could be at "tipping point" if more funding is not found soon.
"Looking at the figures, the expectation would be that we are not spending enough," he writes.
"One clear message from my research is that Wales has been spending money in other areas, such as nation-building, that it should have been spending on education."
The committee will look at government and local authority spending. It will also examine education, health and social services, as well as youth groups and voluntary organisations.
Chaired by the Plaid Cymru AM Helen Mary Jones, the committee will take evidence from interested parties, including the education minister Jane Hutt.
Professor Reynolds said he believed the committee wanted a picture of how Wales compares to other parts of the UK and how local authorities spend their cash on children.
His research found that investment in general public services has risen by 8.3 per cent compared with the UK average since devolution, and by 7.2 per cent for Welsh culture, media and sport.
But he also found that Wales's local education authorities are holding back more money from schools than ever - 81 per cent in 2007-08 compared with 76.1 per cent in 2002-03.
In a poll of 100 heads conducted by TES Cymru to accompany the research, 90 per cent said funding was their main concern, and a majority said Wales's children were disadvantaged compared with their counterparts in England.
In reaction to the Reynolds research, the Assembly government said it was "pointless and misleading" to make comparisons with England. It argued that good teaching practices could make up for a lack of funding, and that money did not equate to better standards.
But it did not contest the figures, and it is generally accepted there is less money in the Welsh education system.
Professor Reynolds, page 37.