When the UK's Lever Brothers merged with Margarine Unie of the Netherlands to form Unilever, western economies were approaching a precipice: it was September 1929.

The companies were joining forces not out of any great foresight; rather, the deal came merely because each had started to impinge on the other's business, with the British moving into spreads and the Dutch into soap. But when Wall Street crashed the following month and prices of fats and oils tumbled in the Great Depression that ensued, the creation of Unilever helped the former family businesses survive the crisis.