The long-standing Scottish advantage in spending levels on the major public services has been rapidly converging with the rest of Britain, according to the government's own figures.

The finding runs counter to the argument used by some English politicians that the Treasury has been too generous to Scotland.

According to the SNP, it also represents a challenge to those who argue Scotland benefits from the "union dividend'' resulting from being in the UK.

The calculations on how much is raised and spent in Scotland are highly-contentious. The row intensified yesterday with Scotland's leading public finance expert countering Nationalist claims about government figures.

Professor Arthur Midwinter, official adviser to MSPs on Holyrood's Finance Committee, has analysed the figures and concluded that none of the attacks on the annual Government Revenue and Expenditure in Scotland (GERS) figures has blunted the claim that Scotland has consistently run a fiscal deficit.

Published last month, the headline finding of the latest GERS report was that Scotland was £6bn in deficit, when accounting for tax revenues from Scotland and expenditure within Scotland. Without oil revenues, the government statisticians found Scotland spending in 2004-05 was £11.3bn ahead of the tax take.

The figures also calculate what that means for spending per head, as the Scottish population remains stable and the total UK population grows. Overall, it shows the amount spent was 19.1% above the UK average in 2003-04, and fell to 15.8% the following year.

During that time, there was a sharp increase in the total funding for most areas of public services but the Scottish share has been falling across the board as money is distributed according to the fixed, population-based formula for additional funds.

The major spending headings show a marked decline in Scotland's spending advantage.

In 1990-2000, the average Scot received 26% more education spending than the average for the UK. However, as total spend has grown rapidly, the most recent figures for 2004-05 tie together education and training and show that advantage has fallen to only 6%.

To Nicola Sturgeon, the SNP deputy leader, the figures undermine Labour's emphasis on education in their campaign for re-election in May.

Professor Midwinter has written a paper on GERS ahead of a Holyrood Finance Committee hearing. The adviser's paper comes down strongly against the Nationalist case that the government figures on Scotland's deficit funding are flawed.

It concludes that Scotland has been in persistent fiscal deficit since the GERS exercise began 14 years ago, whether or not oil revenue is included, and that the government figures are consistent with independent research.