GUIDES
A retrospective capacity opinion reconstructs a specific decision at a past date from records and accounts. It must identify the applicable legal test and the limits of that evidence.
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Key v Key [2010] EWHC 408 (Ch).
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A retrospective capacity opinion reconstructs a specific decision at a past date from records and accounts. It must identify the applicable legal test and the limits of that evidence. The sections below explain the evidence, practical steps and limits of the assessment or process.
A retrospective opinion examines capacity for a specific past decision using the records and accounts available. The person may now have changed or died. Identify the act, relevant dates and governing legal question with the instructing lawyer: ordinary testamentary capacity uses Banks v Goodfellow, while other statutory or common-law rules may apply to lifetime acts. The report should explain both what can be inferred and what cannot reliably be reconstructed.
A retrospective mental capacity assessment asks whether a person had capacity for a specific decision at a specific point in the past: when a gift was made, a property transferred, an LPA signed or instructions given. The person may since have deteriorated, or died, so the opinion is constructed from records, documents and accounts rather than from a conventional visit. It is expert reconstruction, not recollection, and its value depends entirely on the rigour of the method.
The need usually arises through dispute: a transaction challenged by family, a probate claim, a Court of Protection application examining past decisions, litigation over a settlement or contract, or a professional retracing whether instructions were validly given. It also arises protectively, where an attorney, deputy or solicitor needs the past position established before the present can be resolved. In every case the question is anchored to a particular decision and a particular date.
The applicable test travels with the decision. Most decisions engage the Mental Capacity Act 2005: understanding, retaining, using or weighing the relevant information and communicating, with any inability caused by an impairment of, or disturbance in the functioning of, the mind or brain, all assessed as at the material time. Wills engage the common law test in Banks v Goodfellow, and our guide to retrospective testamentary capacity addresses that context specifically. Identifying the right test at the right date is the first analytical step.
Where the person is alive, the retrospective question can sometimes be illuminated by assessing them now, because their present abilities, set against the documented course of their condition, help locate what the past position is likely to have been. Where the person has died, the record is all there is, and the discipline shifts entirely to documentary reconstruction. The report should be explicit about which situation it is in and what that means for the confidence its conclusion can carry.
The assessor defines the decision and the material dates, identifies the relevant information that decision engaged, then works through the contemporaneous record: medical and care notes around the dates, professional files and attendance notes, the person's own letters, messages and documents, and the transaction papers themselves. Witness accounts supplement the record. Each source is weighed for proximity to the material time and for the interest of its author, and the functional analysis is built from what the evidence actually shows.
Retrospective work is a specialist discipline. The assessor needs command of the legal tests, experience of reasoning from records rather than presentation, and the forensic habits of provenance, dating and calibrated conclusion, because most retrospective opinions end up read adversarially. Where the opinion will be used in proceedings, it should be prepared to CPR Part 35 standards from the outset, with the expert's overriding duty to the court and the range of reasonable opinion addressed.
The opinion may support capacity, support incapacity or identify that the evidence is insufficient for a firm view. Explain the reasons and limits rather than force certainty. The court applies the relevant burden and standard of proof, which can differ between legal claims, including disputed wills. An expert should not assume one universal burden for every retrospective instruction.
The report should identify the decision and the material dates, the test applied, every source reviewed with its date and provenance, the relevant information for the decision, the evidence bearing on each functional element, the analysis connecting any impairment to the abilities in question and a conclusion with calibrated confidence. Where the opinion is for proceedings, the CPR Part 35 apparatus, instructions, declaration and range of opinion, belongs in it from the first draft.
Define the decision, date and applicable test, identify the sources and explain the reasoning and uncertainty. A retrospective opinion can help frame a dispute but does not determine its outcome or replace legal advice. Consider the scope and permission requirements for expert evidence before commissioning it.
No. A diagnosis alone does not establish incapacity. For a Mental Capacity Act decision, provide practicable support, examine understanding, retention, use or weighing and communication, then explain whether any inability is caused by an impairment or disturbance of mind or brain. The conclusion is specific to the decision and time.
Records near the material date may include medical and care notes, solicitor files, transaction papers, bank records and the person’s own communications. Witness accounts may also matter. Assess each source for detail, reliability, proximity, context and possible interest rather than assuming documents always outweigh recollection. Identify missing evidence and its effect.
Commission a retrospective opinion at the pre-action stage of a dispute: an early expert view on the strength of the capacity evidence frequently determines whether a claim or defence is worth running at all. A conclusion about one decision does not establish capacity for another.
The related pages below explain connected decisions, evidence requirements and legal processes.
Before seeking a report, write down the exact decision, relevant date, reason for concern and intended use. Gather the documents that explain the real options and any communication needs. Check any required form or court direction, agree the scope and total fee, and clarify how missing evidence or further questions will be handled.
A GOOD PLACE TO START
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