Wales stands to benefit economically from the establishment of an elected assembly, according to a new report.

The report by the Institute of Welsh Affairs, published eight days before Wales goes to the polls, seem set to widen a debate which so far has been marked by apathy and has shed little light on economic considerations.

The authors Ross MacKay, director of the Institute of Economic Research at the University of Wales, Bangor, and Rick Audas, of Newcastle University, find that over the past two decades prosperity in Wales has declined relative to the rest of the United Kingdom.

Dissecting the formula under which resources are transferred from central government to the regions they conclude: "Regional transfers to Wales are not notably generous when compared with transfers made in other countries for regions at similar levels of relative prosperity."

The location of government influenced both economic and political decisions. The report maintains that it was difficult to reverse the centralising policies of countries like Britain, but claim that devolution would provide a counterweight to the UK's well-entrenched tendency to accrete power in London.

The disparity between the regions was highlighted, the report points out, by the fact that the South-east of England has a Gross Domestic Product per head ranking of 16th out of 76 European regions, against Wales's 54th place.

In a commentary on the 52-page report Brian Morgan, of the Cardiff Business School and formerly chief economist with the Welsh Development Agency, says that the Welsh Office failed to defend Welsh interests in 1993 when the Government reviewed its development area policy which allocates help to less prosperous areas. Scotland succeeded in keeping its coverage at 46 per cent of the population but in Wales the figure fell from 35 to 15 per cent.

Writing the report's introduction Gerald Holtham, director of the Institute of Public Policy Research, said the document demolishes practically all the economic arguments put up against an assembly. "Given the chance of power to do good it seems extraordinarily pessimistic to reject it [an assembly] on the grounds that it could also do harm."

Meanwhile, the founder of the "Just Say No" campaign launched a bitter attack on the Welsh Office ministerial team working for a "Yes" vote in the referendum. In an interview in the Welsh-Language magazine Barn, Carys Pugh, a founder of the "No" campaign attacked Ron Davies the Secretary of State for Wales, and Peter Hain, a Welsh Office minister.

According to Mrs Pugh, a Labour Party activist from Rhondda, Mr Davies had instructed party members to shut up if they disagreed with the government's devolution plans. "Ron Davies is behaving like Hitler" she told the magazine.

She predicted that if the vote was lost next week Mr Davies and "the grinny Neath boy" will go. Mr Hain is MP for Neath. He is singled out for special treatment apparently because of his background. He was brought up in South Africa and played a leading role in the Anti-Apartheid Movement when he moved to Britain.

In a joint statement Mr Davies and Mr Hain said the personal attacks "are beneath contempt and we intend making no response".