The focus of this study is on how psychological practitioners including, counselling psychologists, clinical psychologists and other therapists carry out clinical work with bilingual interpreters in offering psychological therapy to clients with limited spoken English. All of the eleven volunteer participants were employed by the National Health Service (NHS), and offered therapy as part of the Improving Access to Psychological Therapy (IAPT) services. All the participants had at least one year of experience working with interpreters. Participants were interviewed and the data was analysed using a social constructionist version of Grounded Theory. The findings of this study suggest that there is a tension in therapy that is of a triadic nature. This tension seems to be centred on two separate styles of clinical practice. Practitioners oscillated between considering the relational nature of the therapeutic work as an exclusive dyadic relationship consisting of the client and themselves, and as an inclusive triadic relationship with the contributions of the interpreter. More specifically, practitioners appeared to want to hold onto the traditional dyadic practice of therapy which offered familiarity, certainty and consequently a sense of reassurance. In other words, it seemed that by denying the interpreter affirmation to the clinical work, and thus dismissing their potential influence on the process and progress of the work enabled practitioners to continue perceiving themselves as the professional expert in charge of the therapeutic work. However, at times practitioners spoke from a more reflective stance, in which the clinical work was considered as a triadic process involving the three members of the triad and acknowledged the benefits of working with an interpreter which included: having a better understanding of the cultural meanings that are important for the client; being able to offer a better experience of therapeutic containment; and developing psychological interventions that are client-centred and culturally appropriate. Overall, the findings suggest that the practitioners in this study struggled to establish their position within the triad. In part, this seemed to be related to the difficulty in negotiating the role of the interpreter in the process of therapy and thus developing a co-worker relationship. It is suggested that clinical work carried out with the help of interpreters could be improved by addressing the areas highlighted in this study and supporting both the therapist and the interpreter in working as a team through implementation, training and regulation of best practice guidelines.