Table 1 Initial programme theory explaining how contextual factors may trigger mechanisms that influence staff’s STP enforcement

CMO1: Alignment of staff and overall health promoting culture in the school (C), trigger staff’s acceptance and readiness for STP enforcement (M), which may lead to staff members’ STP enforcement (O)

CMO2: Inclusion of comprehensive and consistent STPs in school policy document that are packed up by legislation (C), trigger priority of abstinence from smoking at school and staff’s significant role in ensuring that (M), which may lead to staff members’ STP enforcement (O)

CMO3: Supportive leadership and management (e.g. senior management’s actions) (C), trigger shared values and motivation for tobacco-free school among staff (M), which may lead to staff members’ STP enforcement (O)

CMO4: Continuous and sustainable focus on STPs and other health issues in school (C), trigger changes in school smoking norms (M), which may lead to staff members’ continuous STP enforcement (O)