The cheekbones are more sharply defined, the hair tinged with grey. Those could be signs of natural ageing for Rajat Gupta, 70, the first Indian Managing Director of McKinsey, rather than the result of almost 19 months in prison for insider trading.

The real difference is that Gupta, trim and dapper as ever, is far more forthcoming an interviewee than he was in the early 2000s. Then, at the height of his powers, even innocuous questions about his creation, the Indian School of Business, yielded non-committal answers. Now, out of prison since 2016, he has plenty to say: Principally, that his ...