The effect of trade protection of infant industries in developing countries on their long-term growth has been widely debated. This column provides evidence on this topic using a novel dataset from the Napoleonic blockade against British trade. The author analyses the effect of this temporary trade protection on the cotton spinning as an infant industry, employing within-country variation in the trade protection. In the short run, better protected regions increased their production capacity in the infant industry. There is a persistence of this productivity in the long run as well.