GUIDES
Capacity is assessed by the person who needs the answer for the decision, proportionately and with support. Specialist evidence or a prescribed professional may be needed for particular forms or proceedings.
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
39 Essex Chambers, Mental Capacity Guidance Note: Carrying out and recording capacity assessments.
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Capacity is assessed by the person who needs the answer for the decision, proportionately and with support. Specialist evidence or a prescribed professional may be needed for particular forms or proceedings. The sections below explain the evidence, practical steps and limits of the assessment or process.
The Mental Capacity Act does not reserve ordinary capacity assessment to one profession. People involved in the decision, including carers, clinicians and solicitors, assess ability proportionately with support and appropriate records. A specialist may be helpful where genuine doubt, complexity or a formal evidential requirement calls for one. Prescribed forms and court rules may impose particular professional or procedural requirements, which must be checked separately.
The Mental Capacity Act 2005 does not reserve capacity assessment to any profession. In daily life, capacity is assessed by whoever needs the answer to act: the carer offering a choice, the nurse seeking consent, the solicitor taking instructions. For formal, decision-specific assessments the field includes registered social workers, doctors, psychiatrists, psychologists, nurses, occupational therapists and speech and language therapists, and the law's concern is the quality of the assessment, not the letters after the assessor's name.
Use an assessment proportionate to the real decision and reason for doubt. Everyday choices may be addressed by the people supporting the person, while significant or disputed decisions may need fuller documented reasoning or specialist evidence. A will, LPA or valuable transaction does not by itself mean everyone needs to buy a separate report. Identify the actual legal test and any prescribed evidence requirement first.
Relevant competence includes the applicable test, identifying salient information, supporting communication, recording observations and explaining any inability and its cause. Professional registration can provide accountability, but does not itself establish specialist expertise. Ask about experience relevant to this decision and person rather than treating volume of assessments as conclusive proof of quality.
Match expertise to the actual decision, communication needs and intended use. A property opinion may need detailed transaction context, a will opinion Banks v Goodfellow, and clinical uncertainty medical input. Court-facing work must meet the rules and directions of the actual forum; CPR Part 35 is not the sole expert-evidence regime. Seniority or profession alone does not answer suitability.
A GP may provide relevant evidence or assessment within their competence and available services. If the practice cannot undertake the work, ask what records or clinical input can be supplied and consider another suitable professional. Do not assume that an independent assessment is automatically quicker, more accurate or required whenever a GP declines.
Doctors and social workers may each provide valuable capacity evidence within their expertise. Diagnostic uncertainty may require medical input, while assessment of daily functioning, communication and support may benefit from other disciplines. Choose the named practitioner for the question and evidence needs. Professional title and frequency of capacity work do not by themselves establish which opinion will carry greater weight.
Consider possible personal or professional interests and disclose relevant connections. Prior knowledge or employment by a care organisation is not automatically a conflict, while a personal stake or an outcome-linked arrangement may undermine objectivity. The assessor should explain the role, evidence and limits and be able to reach an opinion independent of the commissioner’s preferred result.
In practice, choosing an assessor means asking direct questions: their registration and its currency, their volume of decision-specific capacity work, their experience of this decision type, whether they assess in person, what records they will want, their timescale and their availability if questions follow. Clear answers mark the specialist; vagueness about method or reluctance to discuss follow-up marks the assessor to avoid, whatever their title.
Identify who needs the capacity answer and why, then choose a proportionate assessment and record. Seek specialist input where the question or evidence requires it, and check any prescribed signatory or court requirement. Competence, support and reasoning matter; no profession or service label guarantees the result.
No. A diagnosis alone does not establish incapacity. For a Mental Capacity Act decision, provide practicable support, examine understanding, retention, use or weighing and communication, then explain whether any inability is caused by an impairment or disturbance of mind or brain. The conclusion is specific to the decision and time.
Record everyday capacity decisions proportionately, particularly where concerns, support or best-interests action are involved. A formal instruction may require the decision in writing, relevant medical or care records and documents defining the real options. The necessary evidence depends on the issue rather than a strict informal/formal divide.
Instruct a specialist where the decision is significant, contested or court-bound, where the person's presentation is complex, or where earlier informal views conflict with each other. Everyday decisions rarely need formal assessment at all. A conclusion about one decision does not establish capacity for another.
The related pages below explain connected decisions, evidence requirements and legal processes.
Before seeking a report, write down the exact decision, relevant date, reason for concern and intended use. Gather the documents that explain the real options and any communication needs. Check any required form or court direction, agree the scope and total fee, and clarify how missing evidence or further questions will be handled.
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