Tax revenue as a proportion of the British economy has fallen over recent years but is broadly stable when measured over the long term, according to a new OECD survey.

The latest "Revenue statistics" report found that tax receipts fell in most OECD countries between 2000 and 2002, before levelling out in 2003.

Provisional data for 2003 indicates the ratio of tax to GDP is rising in 13 of the 23 countries for which figures are available.

But the Paris-based financial institution said the UK is among a group of countries that saw "large reductions in tax-to-GDP ratios between 2000 and 2003".

The report says this reflects lower personal income tax rates or increased tax credits.

While the largest such reduction was 4.5 per cent in the United States, Britain's ration fell by 2.1 per cent.

Figures compiled for the report indicate that under John Major's Conservatives, total tax revenue as a percentage of GDP stood at 35 per cent in 1995.

By 2000, under Labour, this had jumped to 37.4 per cent but had dropped back to a provisional 35.3 per cent by 2003.

This was well below the average for the 15 European Union members in 2003, which stood at 40.6 per cent.

Separate figures showed that Treasury revenue from environmentally related taxes as a per cent of GDP has fallen under Tony Blair's administration.

In 1998 the figure stood at 3.2 per cent, but by 2001 this had dropped to 2.87 per cent.

However, the report noted that such reductions could reflect a strong increase in market prices for petrol and a subsequent reduction in demand from 1999 to 2000.

"There has been a persistent and largely unbroken upward trend in the ratio of tax to GDP since 1975 across most of the OECD area," said the report.

"Tax-to-GDP ratios have increased the most in countries where the ratio was below or close to 20 per cent in the mid 1970s and several of these countries now have tax-to-GDP ratios that are close to the OECD average.

"Very few countries have consistently resisted this long-term trend.

"Only in the Netherlands is the tax ratio currently below their 1975 level, and in only three other countries, ie Mexico, the United Kingdom and the United States, have tax receipts developed broadly in line with GDP over a long period."