As always with more sweeping banking regulation proposals it's a question of overcoming the accountability defecit with regard to palming of losses onto the public or ensuring that the revenues would end up where they were intended to.
It's an interesting idea but it's so politically sensitive it's hard to see any serious prospect of implementation.
Those to the left are, (sort of fairly) characterised as pursuing it as a punitive measure above anything constructive or progressive
Throw in some right wing sabre rattling about the EU somehow ruining everything and it's stuck as a good argument unlikely to result in anything substantive.
Centre right vs Centre left
http://www.cps.org.uk/files/reports/original/120419103941-timetobinthetobintax.pdf
http://robinhoodtax.org.uk/sites/default/files/Financial_sector_taxes.pdf
