In 2014, six men from Portsmouth left the city to join ISIS in Syria, prompting a media storm and significant tensions among the city’s communities, and influencing the development of the UK’s Prevent Strategy; University of Portsmouth Policing Lecturer David Knowles, who was the officer responsible for the police response to the incidents and became the national lead for Prevent in education, looks back at the impact on the city and policing, and how those events have shaped Prevent over the past decade.