The De Beers "Shadows" campaign, which ran at a time of recession, is estimated to have increased sales by an annual average of 8% over three years. What's more, De Beers profits recovered by 21% in 1993 compared to the previous year.

Renault launched the Clio in 1991, the same year that new car sales in the UK declined by 21%. With advertising awareness of the "Papa and Nicole" campaign peaking at 56%, the Clio delivered increased profit through premium price positioning.

In the 1930s depression, Kellogg's maintained its marketing spend while Post did not. Kellogg then dominated the dry cereal market for the next half-century.

Source: FT desk research