Since 2001, the British state has increased its powers of surveillance for the purposes of countering terrorism. Much of this has been through expansions of the powers of police and security services to engage in covert surveillance and access the personal data of those suspected of involvement in terrorism. Alongside this, however, the last decade has also seen the development of more diffuse practices of monitoring and surveillance as part of efforts to identify and provide support to those deemed ‘vulnerable’ to being drawn into terrorism. Under Prevent, the UK government’s strategy for preventing violent extremism (PVE),1 much of the responsibility was initially placed on the police and on the communities identified as having particularly high levels of vulnerability, which in practice meant Britain’s Muslim communities.2 Subsequently, however, responsibility for PVE has increasingly been shifted onto a broad swathe of professionals engaged in the delivery of public services, including social workers, youth workers, health-care workers, prison staff, school teachers, and college and university lecturers.3