One of the main reasons for prolonged duration of mechanical restraint is patient behaviour in relation to the clinician-patient alliance. This article reports on the forensic mental health clinicians experiences of the clinician-patient alliance during mechanical restraint, and their assessment of parameters of alliance regarding the patient's readiness to be released from restraint. We used a qualitative, descriptive approach and conducted focus group interviews with nurses, nurse assistants and social and healthcare assistants. The results show that a pre-established personal clinician-patient alliance formed the basis for entering into, and weighing the quality of, the alliance during mechanical restraint. In consideration of the patient's psychiatric condition, the clinicians observed and assessed two quality parameters for the alliance: 'the patient's insight into or understanding of present situation' (e.g. the reasons for mechanical restraint and the behaviour required of the patient to discontinue restraint) and 'the patient's ability to have good and stable contact and cooperation with and across clinicians. These assessments were included, as a total picture of the quality of the alliance with the patient', in the overall team assessment of the patient's readiness to be released from mechanical restraint. The results contribute to inform the development of a short-term risk assessment instrument, with the aim of reducing the duration of mechanical restraint.