Eighty secondary schools were surveyed by researchers

The Secondary Headteachers Association (SHA) said its study showed schools "lost out" by an average of �150 to �200 per pupil in 2003-4.

It surveyed 80 secondary schools of all kinds in 19 local authority areas.

But Welsh assembly education minister Jane Davidson said funding in Wales was at "an all-time high".

The SHA report claimed that schools in Wales "appear to receive significantly less than their English counterparts" in terms of funding delegated by local authorities.

It also said that schools in Wales did not have access to the same range of central funding grants as the English schools.

The study concluded that: "The effects of such a substantial shortfall on individual schools affect all aspects of their operation".

Jane Davidson said comparisons with England was not a key issue

It highlighted areas such as staffing levels and learning resources, as well as saying curriculum developments were being "stifled".

"In this report, SHA calls on the Welsh Assembly Government to take on board these concerns and commission a fundamental, independent review of school funding in Wales," it added.

Ms Davidson said she was disappointed the SHA had not discussed the report with the assembly government before publication.

"The key issue about funding for schools in Wales is not comparison with England but whether schools in Wales have the resources they need to do the job," she said.

She added that the Education and Lifelong Learning Committee was due to consider an assembly government paper on funding comparisons in April.

Figures from the assembly government claim the average budgeted per pupil spend in Wales for 2003-04 was �3,668, compared to �3,697 in England.

Different sizes

The SHA report said its funding concerns were first raised at its annual conference in December 2003, but its request for an independent review of school funding was refused.

It commissioned its own research and revealed its initial findings in December 2004, before this definitive report was published on Thursday.

It analysed 80 schools of different sizes, and schools with and without sixth form pupils, and compared each group with similar schools in the south west and north west of England.