While the process by which a person becomes part of a terrorist group is different in every case, there are patterns and similarities in the ways people are radicalised. Identifying them is a big part of what our security services do nowadays, looking at individual behaviour to try to understand who may end up taking a path towards violence. Joan Smith’s new book, Home Grown, seeks to identify one set of indicators, focusing on misogyny and domestic violence. It is not based on data-driven research. Rather, it relies on anecdotal evidence, drawing on a somewhat random set of case studies from Western societies in recent years. But that does not stop it from being a very stimulating meditation on a topic on which gallons of ink have already been spilled.

Understanding the ‘close link between private and public violence’, Smith suggests, can provide a ‘new way’ of identifying potential terrorists. Her main point is that if you dig into the backgrounds of those who commit terrorist acts, you will find life stories littered with abuse at home –