Introduction: Evaluating care that is not credible to its practitioners or patients will result in a gap between evidence and practice and the potential value, or harm, of the intervention may be underestimated. Our aim was to develop a pragmatic trial that would have better model validity and credibility than trials to date in this clinical area. Methods: In-depth interviews; a nominal consensus technique and five arm pilot trial conducted in UK primary care using counseling and usual general practitioner (GP) care as comparisons for acupuncture. Findings: Patients with long standing, severe illness that had not responded, or partially responded to conventional treatments may be interested in using acupuncture and participating in a trial. Using a database method to recruit, pilot trial patients were mostly severely depressed (87.5%); chronically ill (60% with 3+ previous episodes), with high levels of comorbidity, and medication use. Acupuncture was as credible to pilot trial participants as usual GP care and more credible than counseling: most patients (62.5%) preferred to be allocated to acupuncture, rating it more highly at baseline than counseling or usual GP care as potentially able to benefit their depression (P = 0.002). Disparities were identified in the working models of acupuncturists and counselors that suggest inherent differences between interventions in terms of the process and intended potential outcomes of therapy, as well as the interaction between patients and therapists. Conclusion: The Medical Research Council (MRC) framework with its phased, mixed method approach has helped to develop research that has better model validity than trials to date in this field. The next phase of research will need to involve acupuncture and counseling practitioners to help researchers to develop realistic and credible care packages for a full-scale trial, where patients are likely to be severely and chronically ill.