Rupert Merson fell into lecturing at London Business School after a colleague bottled out of giving a talk. “He said he had double booked with a client meeting, but I think he had lost his nerve,” Mr Merson, a partner at accounting firm BDO, says. “He knew I was a sucker for getting up in front of an audience.”

The topic was financing start-ups, something Mr Merson had written books about, so he felt confident explaining it to a class of MBA students and was invited back a few months later to jointly teach a finance course.

Mr Merson revelled in the lecturing role to such an extent that he took early retirement from BDO, becoming an adjunct professor — a purely teaching role — of management and entrepreneurship. He had an office on the top floor of the main LBS campus building, overlooking Regent’s Park.