Conceptualising ‘Undue Influence’ in Decision-Making Support for People with Mental Disabilities

A crucial question in relation to support designed to enable the legal capacity of people with mental disabilities concerns when support constitutes undue influence. This article addresses this question in order to facilitate the development of law and policy in England and Wales, by providing a normative analysis of the different approaches to undue influence across decisions about property, contracts, health, finances, and accommodation. These are all potential contexts for supporting legal capacity, and, in doing so, the article compares approaches to undue influence that are rarely considered together.Drawing on the UN Convention on the Rights of Persons with Disabilities, third sector and public body documents, and law in England and Wales, the analysis identifies six models that conceptualise undue influence in terms of: modes of influence; an overborne will; an inference from the situation; an overborne will understood as a mental incapacity; an overborne will in connection with vulnerability; and impaired discursive control. This final approach is a novel proposal for understanding undue influence. The analysis highlights key policy-relevant issues that distinguish the models, and generates a deliberative framework for navigating them, with the ‘overborne will’, ‘inference-based’, and ‘discursive control’ models identified as potentially fitting for the support context.