The aims were to develop and operationalise a method of identifying patients at increased risk of adverse outcomes due to clinical and systems complexity within consultation-liaison psychiatry (CLP), and to formalise escalation processes for enhanced input with targeted clinical and organisational support. The literature pertaining to methods for identifying and responding to complexity in general hospital settings was reviewed. An Escalation Tool operationalising the identification of complexity and response pathways was devised and tested. Feedback on the face validity and utility guided refinement. Two established tools that assess complexity, INTERMED and the Patient-Centred Accreditation method (PCAM) and a novel 'episode complexity' screening method, were identified and informed the development of a tool for identifying and responding to complexity, which was then piloted. The tool was deemed useful, notwithstanding variability in scoring. The Escalation Tool combined elements of existing measures to identify complexity in general hospital inpatients and guide pathways for action. It was well received and considered feasible for implementation, with local adaptation according to available resources.