The tax system needs to be more effective to boost research and development spending in the West Midlands, according to Kevin Honey, a partner at the Birmingham office of Ernst & Young.
He hit out even though he backs the £1 billion tax credit scheme where businesses are given incentives to encourage them to invest in R&D.
The scheme makes it possible for companies to receive additional tax relief in respect of such spending, while smaller businesses can even claim cash back as an extra incentive.
Mr Honey said: "The R&D tax credit system is excellent in principle, although it could be working more effectively.
"A very small minority of inspectors are being confrontational rather than enabling, setting out their stall to prevent claims from succeeding rather than adopting a positive stance.
"In an area like R&D, where there can be fairly complex questions of defining spending this has proved to be a problem for some businesses.
"The Revenue's positioning and central specialists are commercial and supportive, as are the majority of inspectors who deal with R&D. They regularly consult on improving the regime and usually listen to practical suggestions. I would like to see the Chancellor announce a real push to encourage the Inland Revenue to adopt a positive approach."
His call comes in the wake of worrying signs of Europe slipping behind in the vital R&D race. A survey by the Department of Trade and Industry showed that Europe had managed a two per cent rise in spending in 2004/5 while the US and Asia achieved seven per cent growth.
Mr Honey is sceptical of such comparisons.
He said: "Much of the spending by businesses on R&D is not identified as an expense as such in the financial statements of UK companies so published figures tend to underestimate the totals.
"Nevertheless, there is room for more spending in this vital area and this is why I would like to see the Revenue take action. In addition, firms often fail to claim on some of the more commercial, product development expenditure. They may either not record product development costs appropriately or fully appreciate the extent of the scheme.
"While it is not necessarily original research, this kind of development spending is vital to our ability to compete.
"A sustained effort to increase the awareness of businesses on this point will pay dividends."
Some other initiatives have not proved themselves at all, he suggests.
"A scheme introduced five years ago to give smaller businesses the opportunity to tender for Government R&D contracts was supposed to have generated £50 million of opportunities a year but in the last two years, only £2 million of such contracts were publicised."