How much will the credit crunch cost?

The IMF has come up with some estimates of the cost of all the bailouts, quantitative easing etc. including possible losses on the various loan guarantees and insurance schemes. See a nice article in Stephanie Flanders's blog for details, but the bottom line seems to be around 9% of UK GDP. This is the estimated cost to the UK taxpayer of these schemes, not the total cost of the recession (which could be anything). Can we afford it? The UK entered the credit crunch with a public debt to GDP ratio of 43% (end 2006) and the IMF reckon this will go up to 77%. This is basically the ratio of what the government owes (to anyone, including UK residents) to our income. The 43% figure was quite low - the G20 average was 78%, with Japan at 195% - so it does not appear to be too worrisome. If all this is correct, the credit crunch will be small beer in comparison to the second world war.