The UK Parliament's Public Accounts Committee (PAC) has revived the idea that banks should pay more for the government protection they enjoy.In a report released yesterday, the PAC called on the UK Government to reassess the fees it charges for its credit guarantee scheme. That is the UK scheme created in October 2008 to ensure banks had liquidity, capital and loan funds during the 2008 crisis.In an earlier 2009 report, the PAC had concluded that the UK Government was justified in taking actions, including recapitalising Lloyds and the Royal Bank of Scotland, nationalising Northern Rock and guaranteeing customer deposits of up to £50,000.Yesterday's report says the maximum amount that could be paid by the taxpayer through the schemes has fallen sharply from the late 2009 figure of £955 billion. But taxpayer exposures still sits at £512 billion - and the government still retains "the unquantifiable ultimate risk of supporting banks should they threaten the stability of the overall financial system".The government should now review the fees it charges for essentially insuring against bank defaults, the report says.The concept of charging more fully for prudential regulatory and liquidity relief services was floated by the IMF a year ago. The UK PAC's comments suggest the idea has not yet dwindled away.