I think 'the cuts' and 'the banking crisis' are two separate issues. It keeps getting dumbed-down to the populus that everything would be peachy if only the banks were better managed, paying more back into society or giving up bonuses... but it ain't that simple. The cuts aren't being implemented to pay for the banking crisis, past or future. They are being implemented, together with tax-rises, to balance the national books better and reduce the deficit - the ongoing difference between tax revenues and government spending. They don't eliminate the deficit, not even close. And they don't do anything to reduce the national debt whatsoever.
Well, you're wrong, because the deficit was at 3% before the financial crisis. It was the financial crisis which caused it to jump to 11% and made interest payments unpayable.
The UK doesn't spend that much on public spending. For example on health, in 2007, it spent (as a percentage of GDP), the same as Malta and Portugal, and less than:
Iceland, France, Norway, Germany, Austria, Palestine, Sweden, Luxembourg, Denmark, Timor, Malawi, and São Tomé and Principe.
www.infoplease.com/ipa/A0934554.html