When US drugmaker Valeant collapsed nearly four years ago, there was no shortage of name-calling and blame-gaming. But one narrative cut through the noise: Valeant had gone spectacularly awry under unusual leadership. A few years earlier, the group had hired as its boss a McKinsey executive named Mike Pearson, who had spent 23 years at the consultancy before being parachuted into the real world of running a pharmaceuticals company — with no operational experience.

For a while, business thrived. But the consultant’s business model — egged on by activist investors at ValueAct and Pershing Square — unravelled. Ditching research, boosting revenue at all costs and hiking drug prices wherever possible turned out to be disastrously short-termist.

In some ways it was a replay — without the criminality — of the 2001 Enron scandal, when a more infamous McKinsey alumnus, Jeffrey Skilling, moved from a 10-year career as a consultant into a string of divisional CEO roles at the energy group before rising a decade later to become CEO of the group. He was convicted on charges of fraud and insider trading and spent more than 12 years in prison.