When Australia imposed generic packaging in its war on cigarettes, there was consumer research into the most deterrent colour. Pantone 448 was chosen, a sort of sludgy green-brown. When it was described as ‘olive’, Oz’s federation of olive growers formally complained.

Certainly, colours move us. Interior designers know that yellow makes people angry, while in the US Naval Correctional Center in Seattle, what’s known as Baker-Miller Pink (after the officers who created it) has been found to pacify stroppy recidivists.