This nor any other government for that matter will allow a bank of this size to fail, for numerous reasons, political and financila are two of the main ones.
The banks also know this , which is why they do what they do, take the risks they do, knowing that they really cant fail !
As for the SFO getting involved, look at their history of failings in massive cases, they arent nicknamed the Seriously Funny Squad for nothing.
investigations on a scale that would be needed for something like this are beyond the capabilities of most organisations.
If we have an inquiry it will be just like most other inquiries, cost millions drag on for ages, a few sacrificial lambs etc etc, to tell us what we already know.....most organisations are run by "crooks" and are corrupt to varying degrees.
too many people know too much about too many other people, nobody is going to shaft anybody because theyre all looking after their own backs
oh hold on a minute thats big business isnt it ?!