EXPECT more green and stealth taxes and a major crackdown on avoidance in Wednesday's Budget, warn accountants.

Chancellor Gordon Brown does not have much leeway to cut or raise taxes dramatically so he could use new anti-avoidance legislation to lever more money out of the current tax rules, they say.

Smith & Williamson private client tax director Andrew Hunt said: "The Budget is almost certain to introduce further layers of tax complexity."

But "whilst targeting anti-avoidance measures are likely - which could be applied retro-spectively - other areas are left vague and open to interpretation.

Yesterday pre-Budget leaks suggested the Chancellor could hike road tax for the least fuel-efficient cars to £400 per year.

Ernst & Young's ITEM Club, which uses the same data as the Treasury to analyse the economy, said Gordon Brown's stealth taxes have driven the real rate of taxation up to 44p for every pound of household income.

In 1996, before Labour came to power, it was 36p per pound, according to ITEM Club chief economic adviser Peter Spencer.

Middle income taxpayers had been hit hardest: "Fiscal drag (not letting tax thresholds keep pace with inflation) and stealth taxation have been working with a vengeance," he said. "This is best illustrated by the increase in the number of top rate tax payers, from 2.1 million in 1997-98 to 3.1 million in 2004-05. During the same period, the number of estates paying inheritance tax increased from 18,000 to 34,000.

"Brown certainly packs his bags at an opportune time. He will probably say he has met his fiscal rules and that he leaves the UK economy to grow by 3.0 per cent this year. What he actually leaves is a large structural deficit and a national tax burden rising to its highest in over 20 years," added Mr Spencer.

Last week Institute of Chartered Accountants in England & Wales deputy president David Furst said the tax system was too complex. He accused the Chancellor and HM Revenue & Customs of being draconian.

"HMRC appears to have taken on the culture of Customs & Excise, where collection maximisation is the main driver," Mr Furst told the Southern Society of Accountants annual dinner.