Author and Publication
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Citation
Department for Constitutional Affairs (2007) Mental Capacity Act 2005: Code of Practice. London: The Stationery Office.
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 complete a COP3 assessment?
A COP3 Part B can be completed by a range of practitioners, not only doctors. The form provides for registered medical practitioners, psychiatrists, psychologists, social workers, nurses and occupational therapists, provided the assessor has appropriate expertise, knowledge of the person's condition and applies the Mental Capacity Act 2005 to the specific decisions in the application. What the court weighs is not the professional title but the quality of the decision-specific reasoning. This guide explains who is suitable, when specialist expertise matters and what the court expects of any assessor.
What the COP3 itself requires of the assessor
The COP3 is completed by a practitioner who sets out their professional qualifications and explains their basis for assessing the person. The court is less concerned with the assessor's job title than with whether the form demonstrates a proper application of the Mental Capacity Act 2005 to the specific decisions in issue. In practice that means the assessor needs both a relevant professional registration and demonstrable competence in capacity assessment, and the form should evidence each.
The professions that commonly complete COP3s
COP3 assessments are completed by registered medical practitioners, psychiatrists, psychologists, registered social workers, nurses and occupational therapists, amongst others. No single profession owns the work. What matters is that the practitioner understands the statutory test, can identify the relevant information for the decisions in question and can conduct and evidence a functional assessment. A registered social worker with substantial capacity experience will often produce stronger evidence than a clinician for whom capacity work is occasional.
Someone who knows the person versus an independent assessor
The form can be completed by a professional already involved in the person's care, such as a GP or treating clinician, or by an independent assessor instructed for the purpose. Prior knowledge brings context, but it is not required, and an independent assessor who visits the person, reviews the records and conducts a structured decision-specific assessment satisfies the court's requirements. Where family dynamics are strained or the application may be contested, independence is often a positive advantage.
Why many GPs decline, and what families can do
Families frequently approach the GP first and find the practice declines, whether due to time pressure, unfamiliarity with the form or policy. This is common and is not a dead end. An independent specialist assessor can be instructed directly, will usually visit at home, and treats the COP3 as a substantive assessment rather than an administrative task. Given that a questioned form delays the whole application, the specialist route is often faster overall even where it takes slightly longer to arrange.
What makes an assessor suitable for a particular case
Suitability is case-specific. An application concerning complex property and financial affairs calls for an assessor comfortable with financial capacity at that level of complexity. A person with a learning disability, dementia or communication needs calls for an assessor skilled in adapting the assessment, taking practicable steps and evidencing them. Where litigation or family conflict is foreseeable, the assessor should be capable of producing evidence that will withstand scrutiny, because the COP3 may be the document everything later turns upon.
Independence and conflicts of interest
The assessor should hold no interest in the outcome. A practitioner closely connected to the proposed deputy, employed by a party who benefits financially or otherwise conflicted invites challenge to the evidence however sound the assessment. Professional independence, transparently stated on the form, protects the application, protects the person and protects the practitioner, and it is one of the simplest quality markers for families and solicitors to check before instructing.
What to check before instructing an assessor
Before instructing, it is reasonable to ask about professional registration, experience of COP3 and Court of Protection work specifically, whether the assessment will be conducted in person, what records the assessor wishes to see, the timescale to a completed form and what happens if the court raises questions afterwards. An assessor who welcomes those questions and answers them plainly is usually the right kind of assessor, whilst reluctance to discuss method or availability for follow-up is a warning sign.
What the completed assessment should demonstrate
Whoever completes it, the finished COP3 should identify the specific decisions assessed, the relevant information for each, the practicable steps taken to support the person, the functional analysis against understanding, retaining, using or weighing and communicating, the impairment identified and the causative link between that impairment and the inability found. A form that demonstrates this reasoning supports the application regardless of the assessor's profession; a form that does not will struggle regardless of the letters after the signature.
Key takeaway
The COP3 can be completed by a range of registered professionals, and the court's real concern is the quality of the assessment rather than the assessor's title. Choose a practitioner with genuine Mental Capacity Act expertise, suited to the person's circumstances and independent of the outcome, and confirm before instructing that the assessment will be conducted and evidenced properly, because the form is only ever as strong as the assessment behind it.
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 COP3 Mental Capacity Assessment?
Whoever completes Part B should have access to the COP1, the relevant medical and care records and clear instructions identifying the decisions to be assessed. An assessor working without the underlying records, or without knowing precisely which decisions the application concerns, produces exactly the kind of general-purpose COP3 the court questions.
When is a formal assessment for COP3 Mental Capacity Assessment useful?
Specialist input matters most where the presentation is complex: fluctuating conditions, rarer diagnoses, significant communication needs or contested family circumstances. In those cases an assessor experienced in decision-specific capacity work, supported by internal peer review, materially reduces the risk of the evidence being questioned.
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.
Looking for the right COP3 assessor?
Nellie Supports completes COP3 assessments through a permanent employed team of registered professionals, with every report peer reviewed before delivery, across England and Wales. Call 0333 987 5118 or visit the COP3 assessment service page.