I examine the factors facilitating or hindering collusion using a comprehensive data set on the incidence of price–fixing across UK manufacturing industries in the 1950s. The econometric results suggest that collusion is more likely the higher the degree of capital intensity and less likely in advertising–intensive than in low–advertising industries. There is also some evidence of a non–monotonic relationship between market growth and the likelihood of collusion. There is no clear link between concentration and the incidence of collusion.