Before he was elected governor of Massachusetts, and even before he rescued the 2002 Salt Lake City Olympic Games, Mitt Romney was known in business circles as the venture capitalist with the golden touch.

During his 14 years at the helm of Bain Capital, the Boston-based private equity firm, Mr Romney earned a reputation for an owlish knack for appraising opportunities - spotting start-ups with lucrative potential and taking troubled, undervalued companies and retooling their business models.