Much of the debate on banking and economic policy are simply beyond my comprehension. It is rare to have a straight forward explanation, although I did enjoy Robert Peston's programme last night; which is summarised here:http://www.bbc.co.uk/news/business-18088540

Or just this opening paragraph:
Creating the currency union was not a random act of collective economic suicide, but was in some senses a rational or even noble project that was either premature or too late. The tragedy was that a succession of post-war leaders, whose intentions would be seen by many as honourable, made a series of disastrously ill-timed decisions.
There is a link to the broadcast, but as some know the BBC sometimes declines to let others watch:http://www.bbc.co.uk/programmes/b01hy4xr

Mr Peston is very unpopular with bankers and others here, he is often accused of causing the fall of Northern Rock by his reporting.