A long-term reform of Britain's tax system is vital, the Conservatives are set to say.

Shadow chancellor Oliver Letwin will claim on Monday that chancellor Gordon Brown's new taxes are damaging productivity and "misleading" taxpayers.

In a lecture to the Politea think tank this evening Letwin will call for a methodical overhaul of Britain's tax structures.

Letwin will accuse Brown of presiding over an ever more complex tax structure - dubbed "Gordonomics".

He will also claim that the public does not interpret spending on services as an open-ended commitment."Taxpayers are increasingly disinclined to see their own money merely thrown at problems, when it is plain that the old prescriptions don't work," he will say.Letwin will pledge that an incoming Conservative government would start a review that would focus on competitiveness, efficiency, transparency and fairness.

"Our plans for radical reform of the NHS and schools are aimed at changing the culture and getting more 'bang for the buck' - by giving patients and parents the power to take taxpayers' money to the hospitals and schools of their choice, so that we can remove the vast top down bureaucratic systems and let the professionals get on with the job of satisfying the demands of their patients and parents," he will say.