AIM: To evaluate an intervention (a film and electronic leaflet) disseminated via text message by general practices to promote COVID-19 preventative behaviours in Black and South Asian communities. METHODS: We carried out a before-and-after questionnaire study of attitudes to and implementation of COVID-19 preventative behaviours, and qualitative interviews about the intervention, with people registered with 26 general practices in England who identified as Black or South Asian. RESULTS: In the 108 people who completed both questionnaires, we found no significant change in attitudes to and implementation of COVID-19 preventative behaviours, although power was too low to detect significant effects. A key qualitative finding was that participants felt they did not 'belong' to the group targeted by the intervention. CONCLUSION: Interventions targeting ethnic minorities in the UK need to acknowledge the heterogeneity of experience and circumstances of the target group so that people feel that the intervention is relevant to them.