‘Start Telling Us Now About AI Use’: Mrs Justice Joanna Smith’s Warning to Expert Witnesses and the 30 November 2026 RICS Standard – What It Means for Surveyor Expert Evidence in Wimbledon Property Disputes (November 2026)

There is no court rule yet requiring an expert to say whether artificial intelligence helped write a report. A High Court judge has told experts not to wait for one. Speaking at the Bond Solon Expert Witness Conference at Church House, Westminster, reported by the Law Society Gazette on 10 November 2026, Mrs Justice Joanna Smith urged expert witnesses to disclose AI use now and warned that those who do not may face "searching questions in cross-examination" [1]. Three weeks later, on 30 November 2026, the RICS standard on expert witness AI disclosure surveyors must follow comes into force [2].

For surveyors who give evidence in Wimbledon, Merton, Wandsworth and Kingston, on basement extensions that crack a neighbour's wall, on boundaries between Edwardian semis, on mansion-block valuations and on defective loft conversions, this is the month to change how reports are prepared and declared.

Key Takeaways

• Mrs Justice Joanna Smith, interim deputy president of the Business and Property Division and co-chair of the Civil Justice Council working group, urged experts to declare AI use now and to tell instructing solicitors at the outset [1].
• The Civil Justice Council report of 29 October 2026 recommends a rule requiring experts to declare AI use where it generated or influenced the substantive content of a report; no such rule exists yet [1].
• The RICS standard Surveyors acting as expert witnesses, 5th edition, takes effect on 30 November 2026 and requires disclosure of AI use, methods and AI-derived material relied on [2].
• Bond Solon's 2025 survey of 525 experts found 20% used AI, double the previous year, and 89% wanted specific guidance [3].
• The expert's duties to the court are unchanged: independence, honesty and personal responsibility for every opinion.

What the judge said and why it matters now

Mrs Justice Joanna Smith's message was simple. Disclosure matters where AI "may directly or even indirectly generate or influence the content of your evidence". Experts who fail to disclose properly may face "searching questions in cross-examination". The duties owed to the court have not moved: "The advent and rapid development of AI has not changed and will not change those duties." The main risk she identified was "the erosion of independent judgment" [1].

She also looked forward: "The future belongs to experts who understand both the capabilities and the limitations of artificial intelligence" [1].

The speech followed the Civil Justice Council's report the previous week on the use of AI in preparing court documents. The report recommends a rule requiring experts to declare AI use where AI generated or influenced the substantive content of their report, and recommends adding the requirement to the revised guidance on instructing experts in civil claims, which dates from 2014 [1]. Until the Civil Procedure Rule Committee acts, there is no rule, which is exactly why the judge asked experts to act voluntarily.

The CJC recommendation and the RICS standard side by side

Issue	Civil Justice Council (29 October 2026)	RICS 5th edition (from 30 November 2026)
Status	Recommendation for a future rule	Mandatory professional standard for RICS members
Trigger for disclosure	AI generated or influenced the substantive content	AI or similar tools used to produce evidence
What to disclose	A declaration of AI use	The use, the methods and tools, and any AI-derived material relied on
Responsibility	Expert remains responsible	Expert remains personally responsible for opinions
Other duties	Guidance on instructing experts to be updated	Instructions verified and recorded; assumptions and alternatives stated

The RICS 5th edition goes further than AI. Experts must disclose regular reliance on the same instructing party, especially where it provides a large share of income; must state all assumptions and set out alternative conclusions where legal assumptions or professional schools of thought differ; must verify and record instructions and summarise material instructions in the report; and must not enter new conditional fee arrangements, with only a narrow exception for pre-existing arrangements that requires a declaration beginning "I confirm that I am instructed by way of a conditional fee arrangement". Combining the roles of expert and advocate remains exceptional, and the standard repeats the principle that "An expert witness should never assume the role of an advocate". Failures can lead to tribunal criticism, adverse costs orders, contempt proceedings, negligence claims and RICS disciplinary action [2].

How widespread is AI use among experts?

Bond Solon's survey of 525 experts, published with the Law Society Gazette in 2025, found that 20% of experts used AI, double the previous year's share, and that 89% wanted specific guidance on expert use of AI. Mark Solon's advice was direct: "Everything received from AI must be checked and the final report must be in their own words" [3]. The 2026 conference, where the judge spoke, suggests the numbers have only moved one way.

Where AI is and is not acceptable in a surveyor's report

Neither the judge nor RICS bans AI. The line is between tools that help an expert work and tools that replace the expert's judgment.

Generally acceptable, with disclosure where it touches content:

• Transcribing site notes and dictation.
• Formatting, proof-reading and checking references.
• Summarising long disclosure bundles for the expert's own review, provided the expert reads the source documents relied on.

High risk, and never a substitute for the expert:

• Diagnosing the cause of cracking, damp or movement.
• Selecting and weighing comparable evidence in a valuation.
• Interpreting a party wall award, a lease or a conveyance plan.
• Drafting the opinion section.

A practical test: if the expert could not defend a sentence in cross-examination from personal knowledge and inspection, AI should not have written it.

Suggested AI disclosure wording

Surveyors can adopt wording along these lines in the declarations section, adjusted to the facts:

In preparing this report I used artificial intelligence tools for the following purposes only: transcription of site notes and proof-reading. No AI tool was used to generate or influence the substance of my opinions. I have personally verified every factual statement and remain responsible for the whole of this report.

Where AI did influence content, the declaration should say what tool was used, for what, and how the output was checked [2].

What this means for Wimbledon property disputes

South-west London generates a steady flow of disputes where surveyors give expert evidence:

• Party wall damage after basement and side-return extensions in Wimbledon Village and Southfields, where causation turns on crack monitoring and schedules of condition.
• Boundary disputes between semi-detached houses in Raynes Park and Merton Park, where historic plans and measured surveys decide the line.
• Valuation disputes in matrimonial and probate cases, and down-valuations of flats in mansion blocks near the Common.
• Defective works claims over loft conversions, roofing and damp-proofing.

In every one of these, a litigant should now ask the expert three questions before the report is served: Did you use AI? For what? How did you check it? Opponents will ask the same questions in cross-examination, and from 30 November 2026 the RICS standard requires the answers to be in the report already [2].

Checklist for surveyor expert witnesses before 30 November 2026

1. Add an AI-use declaration to every report template, and a nil return where none was used.
2. Tell instructing solicitors at the outset what AI tools, if any, will be used.
3. Keep a log of AI use on each file so the declaration can be proved.
4. Add the income-dependence and conditional-fee declarations required by the 5th edition.
5. Set out assumptions and alternative conclusions in a separate section.
6. Reread CPR Part 35 and Practice Direction 35, in particular the overriding duty in rule 35.3, the statement of truth and the rules on single joint experts and written questions.

Frequently asked questions

Is there a court rule requiring AI disclosure by experts?

Not yet. The Civil Justice Council has recommended one. Mrs Justice Joanna Smith has asked experts to declare AI use voluntarily in the meantime [1].

Does the RICS 5th edition apply outside England and Wales?

Yes. It applies to all RICS members globally, with local law and tribunal rules taking precedence where they conflict [2].

Can an expert use AI at all?

Yes, with disclosure and verification. The expert remains personally responsible for every opinion and must be able to defend it from personal knowledge [1][2].

What happens if AI use is not disclosed?

The judge warned of searching cross-examination. Under the RICS standard, non-compliance can lead to criticism, adverse costs, contempt proceedings, negligence claims and disciplinary action [1][2].

Conclusion

The direction of travel on expert witness AI disclosure surveyors must follow is now fixed. A senior judge has asked for voluntary disclosure immediately, the Civil Justice Council has recommended a rule, and from 30 November 2026 RICS members will be bound to disclose AI use, methods and materials in every expert report.

For surveyors acting in Wimbledon and south-west London disputes, the next steps are to update report templates, log AI use on every file, tell solicitors at the outset, and keep the opinion section entirely the expert's own. For litigants, the next step is to ask the question before the report is served rather than hearing it asked in court.

References

1. Start Telling US Now About AI Use Top Judge Urges Expert Witnesses. stewarthouse.co.uk.
2. Rics 2026 Expert Witness Guidance Key Changes for Surveyors. rimkus.com.
3. 5125046.article. lawgazette.co.uk.