United Kingdom

Five years ago, I began to notice that the perpetrators of some of the worst terrorist attacks had something in common. A high proportion shared a history of assaulting wives, girlfriends and other female relatives, sometimes involving a whole series of victims, long before they attacked total strangers.

In the summer of 2016, for example, when just two terrorist attacks in Florida and the south of France left 135 people dead and hundreds injured, both perpetrators claimed to be Islamists. But I was struck by the fact that each had a horrific record of domestic violence.

A year later, there were four fatal attacks in the UK and all six perpetrators turned out either to have abused women or, in one case, to have witnessed his father abusing his mother and sister. There were striking similarities between the histories of Darren Osborne, the rightwing extremist who drove a van into worshippers leaving a mosque in north London, and Khalid Masood, the Islamist who staged an attack on Westminster Bridge. Both men had criminal records for violent offences – and both had abused women.

I thought these cases challenged conventional wisdom about terrorism, which holds that it is all about ideology. Many fatal terrorist attacks actually appeared to be an escalation of violence that had been going on, sometimes for years, against members of the perpetrator’s family. I was convinced that the police and MI5 needed to change the way they assessed the risk posed by suspects, treating a history of domestic violence as a very significant red flag.