At the Royal Society of the Arts in London an eclectic audience drawn from a range of professions sat down last month to watch a debate between the arch-proponent of “narrow banking” Professor John Kay and a man who then co-ran one of the world’s largest integrated investment banking businesses, JP Morgan’s Bill Winters.

At the outset, the prospects for Winters, who was arguing against the motion "this house believes that the future regulation of financial services requires the separation of retail and wholesale banking activities", did not look good as a snap poll found 57% of those present in favour of the proposals.