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.
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How to instruct a mental capacity assessor
Instructing a mental capacity assessor well takes one letter done properly. Identify the person and the specific decision or decisions, explain why capacity is in doubt, enclose or offer the relevant records, name the deadline and the intended use of the report, whether court, Office of the Public Guardian, solicitor's file or family decision, and confirm consent arrangements and who will attend. Decision-specific instruction is the single biggest determinant of report quality, because an assessor asked whether someone has capacity in general terms can only produce a report that answers the wrong question. This guide provides the checklist and explains each element.
What instructing an assessor involves
Instructing a mental capacity assessor means commissioning a formal, decision-specific assessment: identifying the decision in question, choosing a suitable independent professional, supplying the context and records the assessment needs and agreeing the practical arrangements and timescale. Families, solicitors, deputies, attorneys and other professionals can all instruct directly, and the quality of what comes back is set, more than anything else, by the quality of what is sent out.
Define the decision before anything else
The instruction's first job is naming the decision or decisions precisely: capacity to make this will, sell this property, grant this LPA, litigate this claim, decide between these residence options. Capacity in general is not assessable and a request framed that way invites an unusable report. Where several decisions are in play, list each, because each carries its own test and its own analysis, and where the true concern is a transaction someone else is driving, say that too, since it shapes how the assessment must be designed.
Choose the assessor to fit the instruction
With the decision defined, match the assessor to it: relevant professional registration, demonstrable capacity expertise, experience of this decision type and of the person's likely presentation, independence from everyone with a stake in the outcome and, where court or dispute lies ahead, competence to CPR Part 35 standards. A specialist practice will discuss the match openly and allocate accordingly; reluctance to discuss who will assess and why is a reason to instruct elsewhere.
What to include in the letter of instruction
The letter should state the decision and the test where it is known, the reason capacity is in doubt, the purpose the report will serve and who will rely upon it, the family and professional context including any conflict, the person's communication needs and best times, the timescale and any court dates and the documents enclosed. It should also state what is not known honestly, because an assessor warned of uncertainty designs for it, whilst an assessor given a tidy partial picture inherits its gaps.
The records and documents to enclose
Enclose what the decision touches: medical records or a GP summary, the transaction documents, the draft will or LPA, earlier assessments if any, relevant correspondence and, for court matters, the application or pleadings. Under-instruction is the commonest avoidable defect in capacity evidence, and the cure costs nothing: send the full picture and let the assessor judge relevance, rather than curating the file into the shape of a preferred answer.
Practical arrangements that protect the evidence
Agree arrangements that serve the assessment: a visit where the person is most themselves, usually at home, timed to their best part of the day, with the assessor and the person alone for the substantive assessment and interested parties, however devoted, elsewhere. Where presentation fluctuates, build in the possibility of a second visit from the start. These choices are evidential, not merely courteous, and the report will record them as part of the practicable steps taken.
Timescales, urgency and cost
State the true timetable, court deadlines, exchange dates, a deteriorating condition, and ask directly what is achievable, since specialist practices can usually prioritise genuine urgency if told of it at instruction rather than at delivery. On cost, expect a clear quotation once the decision, complexity and travel are known, and weigh it against what the report protects: transactions, applications and wills whose challenge would cost multiples of any assessment fee.
After delivery: questions, clarification and next steps
Confirm at instruction that the assessor remains available afterwards: to answer reasonable clarification questions, to respond to Part 35 questions where the report enters proceedings and to advise on reassessment if circumstances change. A capacity report often begins a process, deputyship, registration, completion, approval, rather than ending one, and an assessor who stays available through that process is part of what a good instruction secures.
Key takeaway
Instructing a mental capacity assessor well is a sequence: define the decision, match the assessor to it, disclose the full context, enclose the record, arrange the visit around the person and agree timescale, cost and follow-up at the start. Every later strength of the report is planted in that instruction, and an hour spent on it protects everything the assessment exists to secure.
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?
The instruction letter with the decision defined precisely, records or consent to obtain them, the deadline and intended use, and the practical details: where the person lives, communication needs and who should attend. That is the complete instruction pack.
When is a formal assessment for Mental Capacity Assessor useful?
A formally instructed assessment is right whenever the decision carries legal or financial consequence, the report may be scrutinised, or an informal view will not settle the question. If in doubt, a short conversation with the provider clarifies it before any cost is incurred.
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.
Ready to instruct an assessor?
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.