Understanding the implementation, impact and sustainability of Bristol's unhealthy commodity advertising restrictions policy: a qualitative systems-based study of stakeholder perspectives.

Introduction: In 2021, Bristol became the first English local authority (LA) outside London to introduce restrictions on advertisements for high fat, salt and sugar products and other unhealthy commodities (alcohol, gambling and payday loans) on LA outdoor advertising sites (bus shelters and some billboards). This study aimed to explore the policy's acceptability, implementation barriers and facilitators, perceived impacts and considerations for sustaining and wider roll out of the policy. Methods: 22 online semi-structured interviews were conducted with key stakeholders from Bristol-City-Council (n=12), advertising industries (n=3), third-sector advertising and sustainability organisations (n=5) and the Office for Health Improvement and Disparities (n=2). Interview transcripts were analysed using inductive and deductive thematic analyses. Results: Stakeholders acknowledged the importance of this policy as part of a system-wide approach to decrease consumption and use of unhealthy commodities. However, several barriers to behaviour change were recognised: (1) limited scope for change of outdoor advertising exposure, (2) displacment of adverts for unhealthy comodities and (3) adaptations to advertising copy. To sustain the policy, stakeholders highlighted the need for a formal auditing process and continued reviewing and improving of the policy in response to industry adaptations as well as expanding the policy to include private advertising spaces. Conclusion: While the policy was seen as a valuable step towards reducing use and consumption of unhealthy commodities, its impact on behaviour may be limited due to the LA owning relatively little outdoor advertising space and by industry adaptations to enable advertising of unhealthy commodities to continue.