Author and Publication
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Citation
39 Essex Chambers, Mental Capacity Guidance Note: Carrying out and recording capacity assessments.
Copywright
Copyright © 2026 Nellie Supports Ltd. All rights reserved.
This article is made available for general information, education and professional reference. It may be downloaded, printed and shared for non-commercial purposes, provided that it is reproduced in full, is not altered in any way, and is properly cited as the work of Nellie Supports Ltd. This material must not be edited, adapted, sold, republished, incorporated into commercial products, or used for commercial training, assessment, report-writing or advisory services without prior written permission from Nellie Supports Ltd.
This article does not constitute legal advice, clinical advice or a substitute for a decision-specific professional assessment. Where legislation, government guidance, court forms or external professional materials are referred to, those materials remain subject to their own copyright, licensing and re-use terms.
Who can assess mental capacity?
Anyone directly concerned with a decision can assess mental capacity informally, and for everyday decisions carers and family members do so constantly under the Mental Capacity Act 2005. Formal assessments for significant decisions, a will, a property sale, court proceedings or deputyship, are different: they should be completed by a professional with relevant registration, training in the two-stage test and experience of the decision type, such as a specialist social worker, psychologist, nurse or doctor. The law sets no fixed list of professions; what matters is competence for the decision in question. This guide explains who assesses what, and when to instruct a specialist.
No profession owns capacity assessment
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.
The everyday assessor and the formal assessor
Two levels of assessment coexist. Day-to-day decisions are assessed informally by those supporting the person, applying the Act's principles proportionately as choices arise. Significant decisions, transactions, wills, LPAs, court applications, deputyships, call for a formal assessment: a structured, documented, decision-specific exercise producing a report others can rely upon. Most difficulty arises when a significant decision is handled at the informal level, leaving nothing behind that a court, registry or challenger can examine.
What actually qualifies someone to assess
The real qualifications are competencies: command of the statutory test and its case law, the ability to identify the relevant information for the specific decision, skill in supporting communication and taking practicable steps, disciplined recording and the capacity to reason from evidence to conclusion in writing. A professional registration supplies accountability and a foundation, but capacity work is a specialism within every profession that does it, and volume of decision-specific experience is the strongest single indicator.
Matching the assessor to the decision
Different decisions reward different backgrounds. Complex financial and property decisions suit assessors fluent in that subject matter; communication-impaired presentations suit those skilled in adapted assessment; wills engage Banks v Goodfellow, which the assessor must know as law, not just as medicine; and court-facing work needs assessors who write to CPR Part 35 standards. The question to ask is never who is most senior but who is most suited to this decision, this person and the scrutiny this conclusion will meet.
The GP question
Families usually ask the GP first, and many GP practices now decline formal capacity work, citing time, familiarity or policy. That is neither a criticism of GPs nor a dead end: general practice is not built around decision-specific assessment, and an independent specialist assessor, instructed directly, visiting at home and treating the assessment as substantive work, typically produces stronger evidence faster. The GP's records remain valuable input either way, and a good assessor will ask for them.
Doctors and social workers: the false hierarchy
A persistent assumption holds that capacity opinions must be medical, but the statutory test is functional and legal, not diagnostic, and courts accept capacity evidence from any suitably experienced professional. A registered social worker who assesses capacity daily will routinely out-evidence a clinician for whom it is occasional, because the demanding parts, defining the relevant information, evidencing practicable steps, showing the causative link, are assessment craft rather than medicine. Diagnosis matters, and the records supply it; the analysis is the assessor's.
Independence and connection to the outcome
Whoever assesses should hold no stake in the result. An assessor employed by the person proposing the transaction, related to a beneficiary or professionally invested in a particular answer invites challenge regardless of competence, and in contested settings independence is worth as much as expertise. Prior knowledge of the person is neither required nor disqualifying; what matters is that the opinion would have been the same whichever side had asked for it, and that the report demonstrates as much.
Choosing an assessor in practice
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.
Key takeaway
Anyone applying the Act assesses capacity informally every day, but formal decision-specific assessment belongs to professionals with genuine capacity expertise, matched to the decision and independent of its outcome. Choose competence over title, specialism over seniority and independence over convenience, because the assessment's authority comes from its quality, and its quality comes from who conducts it and how.
Frequently asked questions
Does a diagnosis automatically mean someone lacks capacity?
No. A diagnosis may explain why capacity is in doubt, but it does not answer the legal question. The assessment must still consider the specific decision, the relevant information, the support provided and whether the person can understand, retain, use or weigh that information and communicate a decision.
What evidence is useful for Mental Capacity Assessor?
For informal day-to-day decisions, records are rarely needed. For a formal assessment, provide the decision in writing, relevant medical and care records and any legal documents involved, so the professional can anchor the assessment to the specific decision rather than capacity in general.
When is a formal assessment for Mental Capacity Assessor useful?
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.
Related mental capacity assessment pages
These internal links help readers move from this guide to the most relevant Nellie Supports service page, assessment option or legal framework page.
Wondering who should assess?
Nellie Supports provides independent, decision-specific mental capacity assessments across England and Wales through a permanent employed team of registered professionals, with a same working day response to every enquiry and every report peer reviewed before delivery. Call 0333 987 5118 or visit the mental capacity assessment service page.