You wonder how a man with a degree in logic and language came to helm Willis Towers Watson, the insurance broking, risk management and advisory giant; then you sit down with Carl Hess, and it all begins to make sense.

For one thing, Mr Hess, the son of a college don who specialised in Somali history, has spent 34 years in the same firm, during which time he has come to know almost every part of the business, from actuarial work to sales and marketing.