New RICS Expert Witness Standard
What Does It Mean for Property Valuation Experts?
Samantha Johnson
10/6/20263 min read
RICS has published the 5th edition of Surveyors acting as expert witnesses, updating the professional standard for chartered surveyors providing expert evidence.
Published on 30 July 2026, the new standard comes into effect on 30 November 2026 following a four-month transition period.
For solicitors, clients and other professionals instructing property experts, the new standard provides a useful reminder of what should be expected from a surveyor acting as an Expert Witness.
The expert's duty comes first
Perhaps the most important principle is also the simplest.
An Expert Witness's primary duty is to the court or tribunal, not to the client instructing or paying them.
Expert evidence must therefore be independent, impartial and unbiased. An expert should not seek to find the answer which best supports the case of the party instructing them.
This is particularly important in valuation disputes.
Valuation is not always an exact science. Two competent valuers may legitimately reach different conclusions from the same evidence. The role of the Expert Witness is to provide their genuine professional opinion and importantly to explain the evidence, assumptions and reasoning which have led them to that conclusion.
Is the expert actually an expert?
The updated standard places clear emphasis on competence.
Before accepting an instruction, an RICS member must have the appropriate experience, knowledge and expertise for the valuation and must not provide an opinion outside their field of expertise.
For property valuation disputes, this goes beyond simply being a qualified valuer.
The expert should understand the relevant property type, valuation methodology and market. They should also have the ability to analyse the evidence and communicate what can sometimes be complicated valuation reasoning clearly.
This is something instructing parties should consider at the outset.
Independence and conflicts of interest
Independence is fundamental to the Expert Witness role.
Potential conflicts therefore need to be carefully considered before an appointment is accepted.
There can also be circumstances where a surveyor has previously acted as an adviser before subsequently being asked to act as an Expert Witness. The distinction between those roles needs careful consideration.
The updated RICS standard also provides greater clarity around the distinction between an expert and an advocate.
An Expert Witness is there to assist the tribunal with matters within their expertise, not to argue the client's case.
Evidence, assumptions and limitations
A robust expert valuation should do considerably more than provide a valuation figure.
The evidence should clearly identify the main facts and assumptions upon which the opinion is based and should not omit material facts which could be relevant to the conclusion.
Any limitations in the available evidence or information should also be identified.
For valuation evidence, this means explaining the comparable evidence considered and the relevance and weight attached to that evidence. The Expert should also explain the valuation methodology adopted and the reasoning behind the conclusion.
The reader should be able to understand not only what the valuation opinion is but why the valuer has reached it.
In my experience, this is one of the most important aspects of expert valuation work.
A technically sound valuation is important, but so too is the ability to explain a complicated property and valuation issue in a clear and logical way.
What if the evidence changes?
An Expert Witness must remain independent throughout the instruction.
If further evidence becomes available which affects an opinion, the expert needs to consider it objectively. Their role is not to defend an earlier conclusion regardless of subsequent evidence.
That independence is fundamental to the credibility of expert evidence.
It can also assist the parties in identifying where the genuine areas of valuation disagreement lie and potentially narrowing those issues before a matter reaches a hearing.
Fees and modern working practices
The 5th edition also addresses fee arrangements, appointments should not be made on a conditional or deferred fee arrangement.
Whatever technology is used to assist an expert in undertaking their work, responsibility for the expert evidence remains with the individual expert. Any material generated through AI must be stated.
It is worth noting that an Expert Witness appointment is personal. A firm itself is not appointed as the Expert Witness.
For clients and instructing solicitors, it is therefore important to understand who will actually be undertaking the work and ultimately standing behind the professional opinion provided.
Choosing a property valuation Expert Witness
When considering the appointment of a valuation expert, I would suggest looking beyond whether someone is simply an RICS Registered Valuer.
Consider whether they:
have appropriate experience of the relevant property type and market
understand the particular valuation issue in dispute
can demonstrate independence from the parties
can explain complicated valuation evidence clearly
have sufficient resources to meet the required timescales
will personally undertake and stand behind the expert evidence provided.
How Delaford can help
Delaford Property Consultants provides independent property valuation and Expert Witness advice across the South West.
We can assist solicitors, property owners and other professional advisers where an independent valuation opinion is required, including the preparation of CPR compliant Expert Witness reports.
Our work includes property valuation disputes, diminution and Section 18 matters and other circumstances where specialist independent valuation evidence is required.
If you have a matter where valuation evidence may be needed, I am always happy to have an initial conversation to understand the issues and establish whether I can assist.
Samantha Johnson BA (Hons) MRICS IRRV (Hons)
RICS Registered Valuer
Managing Director
Delaford Property Consultants
