The Business on: Sir Ronald Cohen, Adviser, Big Society Bank

The PM's big idea?

Well, sort of. The social investment bank fits in with David Cameron's big society theme, but it's an idea that has been around for years. In fact, Sir Ronald has more claim to the notion than the Prime Minister – a few years back he chaired the inquiry into banks' unclaimed assets that suggested they be put to this use.

What are his qualifications?

Apart from a longstanding involvement with social investment – going back to well before the idea was fashionable – Sir Ronald knows the City inside out. He made his name in the private equity industry, where he was one of the founding partners of Apax. He and Jon Moulton, then of Alchemy, were the first people inducted into the "Private Equity Hall of Fame" when some bright spark came up with the idea in 2002.

He sounds like just the sort of establishment figure the Tories would go for

Don't jump to conclusions. In fact, Sir Ronald's political persuasions are left of centre. He stood for the Liberal Party in parliamentary and European elections in the Seventies, but more recently has been one of Labour's most generous backers.

Crumbs, so Mr Cameron really is harnessing the big society?

Well, he's also asked Nick O'Donohoe, a well-known banker – mainly at JP Morgan, but also at Goldman Sachs – to advise on the Big Society Bank, so it's certainly going to be a bank of all the talents, so to speak.

Tell us more about Sir Ronald

Well, the stellar career in the Cityfollowed an equally impressiveacademic career, including an MBA from Harvard earned after Sir Ronald had graduated from Oxford University, where he was President of the Oxford Union.

Another toff, no doubt?

You're jumping to conclusions again. Sir Ronald's achievements are all the more impressive given that onstarting at a north London grammar school aged 12 in 1957, he spoke only a few words of English. His family had been forced to flee their home in Egypt following the Suez Crisis.