The study protocol and statistical analysis plan are available from the ISRCTN Registry. The datasets generated or analyzed during this study (deidentified participant data and data dictionary) are available from the University of Bath’s Research Data Archive [36]. Data access is restricted and will be made available to approved bona fide researchers after they have signed a data access agreement with the Research Data Services. Participants consented to the sharing of anonymized data at the start of the study. 36. Roy D, Blackwell A, Daryan S, Jacobsen P, Taylor G. In press. In: Dataset for Integrating Online Stop Smoking Support with Online Talking Therapies. Bath. University of Bath; 2025.