Are govt vows to clamp down on tax avoidance a welcome approach or a witch hunt against rich people who aren't breaking the law?

The Westminster Government is vowing to clampdown on financial firms that operate tax avoidance schemes. Tax avoidance is of course legal. But elaborate accountancy schemes to cut tax bills are under attack as never before. Last month the Prime Minister condemned the tax arrangements of comedian Jimmy Carr as "morally wrong". David Cameron's government is now considering forcing accountants to hand over the details of wealthy people who use aggressive tax avoidance schemes. Is this a welcome get-tough approach? Or a witch-hunt against rich people who are breaking no laws?