This is the essential content of the proposals by the EU High Level Expert Group, which I chaired, published last autumn. It is also at the core of the Volcker rule which is being implemented in the US, and the Vickers proposal in the UK. The current legislative proposals which are underway in France and Germany are also in the same vein.
A particular concern of these proposals has been to limit the extent of explicit or implicit public guarantees, so that they would not induce additional risk taking. This kind of competitive distortion could result in securities trading getting concentrated in the largest deposit banks, and these deposit banks becoming enormous risk concentrations built on implicit or even explicit public guarantees.