In fact, a recent lawsuit against the IRS says contingent fees should be allowed .

FORBES: Can Lawyers or Accountants Do Your Taxes on Contingency?

Contingent fees are generally OK in the case of amended tax returns too, although there are timing rules to observe.

FORBES: Can Lawyers or Accountants Do Your Taxes on Contingency?

Ms Smith said her party had ruled out up-front tuition fees and a pure graduate tax and instead declared themselves in favour of a deferred fees system facilitated through income contingent loans.

BBC: Higher education debate