Author and Publication
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Citation
Trustee Act 1925, c. 19. Available at: https://www.legislation.gov.uk/ukpga/Geo5/15-16/19/contents
Copywright
Copywright © 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.
The legal test for capacity does not change with the size of the estate: sections 2 and 3 of the Mental Capacity Act 2005 apply to every deputyship application, whether the person's affairs amount to a pension and a bungalow or trusts, companies and property across several jurisdictions. What changes is the relevant information, because the more complex a person's property and affairs, the more there is to understand, retain, use and weigh, and the more scrutiny the capacity evidence will attract. This guide explains how COP3 assessments work for high-value and complex estates and what instructing solicitors should expect from the evidence.
Value changes the context, not the test
Capacity under the Mental Capacity Act 2005 is decision-specific, so the question in a COP3 assessment is whether the person can make decisions about their own property and financial affairs, and the information relevant to that question scales with the affairs themselves. A person may retain capacity to manage day-to-day spending whilst being unable to weigh decisions about a trading company, an investment portfolio or a trust of which they are both settlor and beneficiary, and a careful assessment identifies that distinction rather than flattening it into a single global answer.
Unconventional is not incapable
Section 1(4) of the Mental Capacity Act 2005 protects the right to make unwise decisions, and it matters most where the stakes are highest. A wealthy person's unconventional financial choices, generous gifts or appetite for risk are not, of themselves, evidence of incapacity, and assessments are sometimes sought as leverage in disputes over exactly these choices. The assessor's discipline is to test the person's ability to understand, retain, use or weigh the relevant information, not to audit the wisdom of their decisions.
The scrutiny complex estates attract
High-value deputyship applications are rarely read once and filed. The capacity evidence may be examined by professional or panel deputies taking on the appointment, by the Office of the Public Guardian in supervision, by family members contesting who should control the estate and, where matters become contentious, by the Court of Protection itself with legal representation on several sides. Evidence prepared for a quiet file rarely survives that reading, so it should be built for an adversarial one from the outset.
Why the standard of the COP3 matters
Weak capacity evidence delays applications, and in a complex estate delay carries a daily cost: assets unmanaged, transactions stalled and family tension compounding whilst nobody has authority to act. Our guide on common reasons COP3 forms are rejected or questioned sets out how often applications founder on evidence that never engaged with the actual decision, and the more complex the affairs, the less forgiving that scrutiny becomes.
The causative link, made explicit
A strong COP3 does not simply record that an impairment exists and conclude that capacity is lacking. It demonstrates how the impairment affects the person's ability to understand, retain, use or weigh the specific information their affairs involve and to communicate a decision, with the practicable support given to the person recorded. The causative link between impairment and inability is the part courts and solicitors probe first, and it is the part generic assessments most often leave implicit.
Engaging with the actual affairs
An assessment that never touches the existence of the trust, the business or the portfolio has not tested the relevant information. That does not require the assessor to value assets or give financial advice; it requires the assessment to present the real shape of the person's affairs at an appropriate level and test whether the person can hold and weigh it. Independence matters equally, because where family members disagree about who should act, the assessor must be visibly independent of every faction, instructed on the evidence as opposed to the outcome.
Discretion and information handling
Complex estates come with sensitive information about assets, family arrangements and business interests, and the practice handling the assessment should be able to evidence how that information is held, shared and destroyed. Expect clear confidentiality arrangements, reports distributed only to those entitled to receive them and a professional infrastructure behind the individual assessor rather than an ad hoc arrangement.
The person before the estate
It is easy, in a case defined by its assets, for the person to disappear behind their balance sheet. The purpose of a capacity assessment is not to protect wealth; it is to protect the person's right to make their own decisions where they can, and to ensure decisions are made properly for them where they cannot. Our assessors work directly with the person, at their pace and in their setting, to ensure their voice sits at the centre of evidence that may determine who controls their affairs for years.
Key takeaway
The estate raises the stakes and the scrutiny, never the legal threshold. For high-value and complex affairs, instruct evidence that engages with the real shape of the assets, makes the causative link explicit, demonstrates independence and keeps the person's voice at the centre. Nellie Supports completes COP3 and Court of Protection capacity assessments across England and Wales as the largest identified specialist private social work and mental capacity assessment practice in England and Wales, with more than 11,000 formal assessments and reports completed, every report peer reviewed before delivery and standard reports in 5 working days from the assessment visit.
Frequently asked questions
Does a large estate need a different kind of capacity assessment?
The legal test is identical. What differs is the relevant information the person must be able to weigh and the depth of evidence the application will need to withstand scrutiny.
Can one assessment cover both everyday finances and complex holdings?
Yes, and a good one will distinguish between them, because capacity is decision-specific and may be retained for some financial decisions whilst absent for others.
Who sees the assessment in a deputyship application?
The Court of Protection and the applicant's solicitors, and potentially the Office of the Public Guardian, proposed deputies and other parties where the application is contested.
Does the assessor need to understand the assets themselves?
The assessor does not value assets or give financial advice, but the assessment must present the real shape of the person's affairs at an appropriate level, because testing capacity against information the person was never given is not a valid assessment.
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.
Deputyship evidence for a complex estate?
Nellie Supports completes COP3 and Court of Protection capacity assessments across England and Wales, with a same working day response and every report peer reviewed before delivery. Call 0333 987 5118 or visit the COP3 mental capacity assessment service page.