In recent years, one of the primary concerns for policymakers and practitioners working in the field of counterterrorism has been over the role of the Internet in the process of radicalisation. There is little doubt that the growth of the Internet, with its ability to connect people and facilitate the dissemination of ideas and information, has had a significant impact on the accessibility and flow of extremist views. It is clear the online domain provides a platform for those with extremist views to communicate, collaborate and convince others to engage with extremism. However, even if the Internet does play a role in the development of extremist views, how often does this translate into acts of extremist offending that result in arrest and conviction?