The Mental Capacity Act 2005

Mental Capacity Assessments

Decision-specific capacity and supported decision-making in England and Wales

01What is the Mental Capacity Act 2005?

The Mental Capacity Act 2005 provides a framework for assessing capacity for a particular decision and for acting or deciding under the Act where a person lacks that capacity. It applies in England and Wales, with most decision-making powers concerning people aged 16 or over. Some matters, including making a person’s own will, require distinct legal tests. Identify the decision and the applicable framework before commissioning evidence.

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England and Wales

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For a decision governed by the Act, ask whether the person can make that decision at the relevant time, with all practicable support. A finding about one decision does not establish incapacity for every other decision.

This guide explains how the Act operates in practice, how the legal test is applied and where capacity assessments commonly fail.

02Decisions covered by the Act

The Act supports people to make their own decisions and provides safeguards when they cannot. The assessment must address the particular decision. Court procedures and some legal decisions have additional requirements:

• Decision-specific mental capacity assessments
• Best interests decision-making
• Deputyship applications and COP3 assessments
• Capacity to grant a Lasting Power of Attorney
• Litigation capacity, with the relevant procedural rules; CPR Parts 21 and 35 apply in civil proceedings where applicable
• Capacity to manage finances, residence decisions and trustee capacity
• Retrospective capacity assessments and disputes
• Safeguards when someone cannot make a particular decision, including best-interests decisions and limits on restrictions of their rights. Safeguarding concerns about abuse or neglect also need the appropriate safeguarding response; they do not, by themselves, establish incapacity.

03Making your own will uses a separate test

Testamentary capacity concerns making or changing your own will. The applicable test is Banks v Goodfellow. It is explained separately from the Mental Capacity Act assessment below.

Read about testamentary capacity assessments

04The five statutory principles

At the heart of the Act sit five mandatory principles. They are not guidance, they are law, and every assessment and decision must demonstrate compliance with them:

• Presumption of capacity. Every adult is presumed to have capacity unless it is established otherwise. Capacity is not removed because a person has a diagnosis, appears vulnerable, makes an unwise decision or disagrees with professionals.
• Support to make a decision. A person must be given all practicable help before being treated as unable to decide, including simplified explanations, visual aids, adjusted timing, communication support and the use of interpreters or advocates.
• The right to make unwise decisions. A decision others consider imprudent does not equal incapacity. The Act protects autonomy, including risky or unconventional choices.
• Best interests. An act done or decision made under the Act for a person who lacks the relevant capacity must be in their best interests. Consider the person’s participation, wishes, feelings, beliefs and values, the relevant circumstances and appropriate consultation.
• Less restrictive options. Before acting or deciding under the Act, consider whether the purpose can be achieved as effectively in a way that restricts the person’s rights and freedom of action less.

05Where capacity assessments go wrong

• Confusing a diagnosis with incapacity
• Failing to identify the specific decision being assessed
• Failing to explain how an impairment causes the difficulty in making the decision
• Inadequate exploration of the use or weigh element
• Over-reliance on risk as evidence of incapacity
• Insufficient evidence gathering

06How capacity is assessed

Assess the particular decision at the time it needs to be made, after taking all practicable steps to help the person decide. The Supreme Court in A Local Authority v JB [2021] UKSC 52 explained the order of the two questions below.

First, can the person make the decision? Consider whether they can understand the relevant information, retain it long enough to decide, use or weigh it and communicate their decision by any means. The information includes the reasonably foreseeable consequences of the available choices and of not deciding.

If the person cannot make the decision despite support, is that inability caused by an impairment of, or disturbance in, the functioning of the mind or brain? The assessment must identify the impairment and explain how it causes the particular inability.

A diagnosis alone does not establish incapacity. The report needs to explain the connection between the impairment and the person’s difficulty in making this decision. It should also consider whether missing information, communication barriers or other circumstances explain the difficulty.

07Who can assess mental capacity?

For everyday decisions, the person directly involved in the care or decision will often consider capacity; a separate specialist report is not always needed. A formal assessor must have the knowledge, skills and experience needed for the specific question. Depending on the instruction, this may be a suitably experienced social worker, doctor, psychologist or other professional. For COP3 and other court evidence, the assessor must also meet the relevant form, rules and court directions. A professional title alone does not establish competence for every assessment.

08Related pages

Mental capacity assessments · COP3 assessments · How to prepare for an assessment

09Frequently Asked Questions

Is the Mental Capacity Act 2005 means-tested?

No. The Act governs decision-making capacity, not funding.

Does a diagnosis automatically mean someone lacks capacity?

No. A diagnosis alone is insufficient. The functional test must be applied, and the impairment must be shown to cause the inability to decide.

Can capacity fluctuate?

Yes. Capacity can vary with time, health and the complexity of the decision, which is why assessments are decision-specific and time-specific.

Who can carry out a mental capacity assessment?

The appropriate assessor depends on the decision and the evidence required. Everyday care decisions may be assessed by the person directly involved. Formal assessments need someone with relevant competence and experience; suitably experienced social workers can provide capacity evidence. Any court form, expert-evidence rules and directions must also be checked.

Is testamentary capacity governed by the MCA?

Making or changing your own will is assessed under the common-law Banks v Goodfellow test. It is a separate testamentary capacity assessment, rather than an assessment under sections 2 and 3 of the Mental Capacity Act. A statutory will made by the Court of Protection is a different legal process.

This guide is general information about the Mental Capacity Act 2005 in England and Wales, not legal advice, and does not create a professional relationship. Nellie Supports provides independent social work assessment, evidence and advocacy support. We do not provide regulated legal advice, and where a legal remedy is needed we will say so and support your solicitor's work.

10Prepare the decision and supporting information

Start with a short explanation of the decision, the person’s location, any deadline and any communication needs. We will explain which records are needed and how to share them securely. Please do not send medical, legal or financial records through the general enquiry form.

11Primary sources and official guidance

Mental Capacity Act 2005

Mental Capacity Act Code of Practice