Basically, the major banks have colluded and lied spectacularly about their numbers to modify their LIBOR ratings to profit massively at the detriment to pretty much everyone else.
Basically, the international finance system is a sham. This isn't one or two bad banks, they would all have to have agreed to this for it to work. The top 16 international banks are rotten to the core. There is no competition, it's a cartel, little different from OPEC meeting to declare oil will cost $110/barrel. I personally am waiting on the Libertarians' spin on how this is caused by regulations, and the free market would fix this if only we'd just let it.