Mental Capacity Act 2008 · 2020 Revised Edition · Part 2 · Persons Who Lack Capacity
5. Inability to make decisions
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A person cannot decide if they cannot understand, retain or weigh the relevant information, or communicate their decision. A person who understands a suitable explanation, such as in simple language, is not treated as unable to understand. Retaining information only briefly does not make a person unable to decide. Relevant information includes the likely results of deciding or not deciding.
Summary · Drafted with AI, checked against the official text on 30 Sep 2026.
For the purposes of section 4, a person is unable to make a decision for himself or herself if the person is unable —
to understand the information relevant to the decision;
to retain that information;
to use or weigh that information as part of the process of making the decision; or
to communicate his or her decision (whether by talking, using sign language or any other means).
A person is not to be regarded as unable to understand the information relevant to a decision if the person is able to understand an explanation of it given to him or her in a way that is appropriate to his or her circumstances (using simple language, visual aids or any other means).
The fact that a person is able to retain the information relevant to a decision for a short period only does not prevent the person from being regarded as able to make the decision.
The information relevant to a decision includes information about the reasonably foreseeable consequences of —
deciding one way or another; or
failing to make the decision.