Managing director, David Stothard, explores the difference between an expert advisor and an expert witness with the example of expert Mr Mark Fairhurst in the recent case of Aston Risk Management Ltd v Jones and others.

The ‘expert advisor’

Each change in the rules of litigation can lead to unexpected consequences. Lord Woolf’s reforms resulted in it becoming ‘altogether exceptional for experts to have to appear in court’.

His emphasis on the use of single and single joint expert witnesses prompted the emergence of the ‘expert advisor’. This is an expert witness retained by one party only to advise rather than to provide CPR compliant evidence for the court case.

Such an expert will usually be asked to provide a preliminary opinion to help the lawyers better understand the issues in their case or to critique the evidence of the opponent’s expert in the case. This can enable a party to either ask pertinent questions of the report or perhaps, considering what they regard as unsatisfactory answers, to make the argument to the court that they should be allowed to obtain their own expert witness evidence.

The challenge for the expert witness in such circumstances is that once appointed to give evidence in the case, the obligations of CPR 35 then apply to them, and they must cease to be a partisan advisor to the party instructing them and replace that duty with the overriding and objective duty to the court. That may not be easy to do and can result in complex issues for the expert witness to address.

CPR 35 and PD 35

The Civil Procedure Rules Part 35(3) makes the expert witnesses’ overriding duty to the court clear with commendable simplicity:

(1) It is the duty of experts to help the court on matters within their expertise.
(2) This duty overrides any obligation to the person from whom experts have received instructions or by whom they are paid.

Practice Direction 35 expands on that as follows:

2.1 Expert evidence should be the independent product of the expert uninfluenced by the pressures of litigation.
2.2 Experts should assist the court by providing objective, unbiased opinions on matters within their expertise, and should not assume the role of an advocate.
2.3 Experts should consider all material facts, including those which might detract from their opinions.
3.1 An expert’s report should be addressed to the court and not to the party from whom the expert has received instructions.

The challenge of meeting those requirements having started from the position of an expert for one party, advising that party rather than the court, is inevitably one which invites an allegation of partisanship or lack of independence.

The Civil Justice Council’s (CJC’s) Guidance for the Instruction of Experts in Civil Claims has a quasi-judicial standing, being referred to directly in PD 35.

Although it covers a wide range of issues, the aim is to enable clearer understanding by expert witnesses and those instructing them of best practice to comply with the rules and practice direction. It also specifically addresses the position of the expert advisor who is subsequently instructed as an expert witness in the case. The guidance does not change the CPR requirements but expands on them in a narrative form to assist comprehension and sensible application of the rules.

Challenges with the expert advisor role

The issue of the expert advisor is directly addressed as follows:

6. Advice from an expert before proceedings are started which the parties do not intend to rely upon in litigation is likely to be confidential; this guidance does not apply then. The same applies where, after the commencement of proceedings, experts are instructed only to advise (e.g. to comment upon a single joint expert’s report) and not to prepare evidence for the proceedings. The expert’s role then is that of an expert advisor.

7. However this guidance does apply if experts who were formerly instructed only to advise, are later instructed as an expert witness to prepare or give evidence in the proceedings.
The guidance highlights the risk in this situation in paragraph 23 which deals with matters which the expert must consider before accepting a CPR 35 instruction:
The instructions and/or work have, for any reason, placed them in conflict with their duties as an expert. Where an expert advisor is approached to act as an expert witness they will need to consider carefully whether they can accept a role as expert witness.

    This requires particularly careful consideration bearing in mind that at paragraph 11 of the guidance it says:

    A useful test of “independence” is that the expert would express the same opinion if given the same instructions by another party. Experts should not take it upon themselves to promote the point of view of the party instructing them or engage in the role of advocates or mediators.

    An expert will need to give very careful thought to their role in the case already and whether they can move from a partisan position where they have been promoting the interests of one party, to a neutral independent position where their advice is directed to the court and not either party.

    The case of Mr Fairhurst

    This issue was directly considered recently by the High Court in Aston Risk Management Ltd v Jones and others [2024] EWHC 252 (see particularly paragraph 47 onwards). The evidence of Mr Mark Fairhurst, a forensic accountant, was disputed on this basis.

    The case related to a technical issue as to whether Mr Lee Jones had acted in breach of his duties as a director in making payments to the other defendants and disposing of company assets before it went into administration. There had already been one trial which decided that there was liability for breaches committed and this second trial was to decide how much compensation should be awarded to the claimant.

    Two of the defendants alleged that Mr Fairhurst should not be regarded as an independent expert witness, and therefore that his evidence should be dismissed as being inadmissible. The basis for this was the contention that Mr Fairhurst was engaged at an early stage by the claimant to provide advice and that this compromised his independence and demonstrated that he lacked the necessary independence to give expert evidence, or at least that the judge should attach no, or no significant weight to it.

    This was an incredibly high risk situation for the claimant as the result would be that their case for losses had not been proved.

    HHJ Cawson KC made the following findings in his judgment, which merit reading in full:

    48. During the course of the hearing, and in the face of Mr Jones’ submissions, ARM voluntarily disclosed a “Preliminary Quantum Appraisal” dated 6 March 2020 prepared by Mr Fairhurst – a document that would, but for such waiver, probably have been privileged (see Jackson v Marley Developments Ltd [2004] 1 WLR 2926). I note the following comments made by Mr Fairhurst in his introduction to this document:

    “I am instructed in this matter by Fieldfisher, Solicitors, who act on behalf of the claimant Aston Risk Management Limited (“ARML”).

    “My instructions are to undertake a preliminary appraisal of the loss of claim, as presented, and to provide a preliminary assessment of the quantum aspects of the constituent heads of loss as set out in the draft claim.

    “I am instructed in this matter as an accountant. My comments within this appraisal limited to my expertise as an accountant. I am not qualified to comment on matters of law nor am I qualified to comment on the legal merits of the claim.

    “This appraisal is prepared solely for the purpose of assisting my instructing solicitors in the furtherance of litigation and in assisting those instructing me to better understand the potential risk elements solely from a quantum viewpoint in advance of a proposed litigation funding application.”

    49. As I see it, the purpose of this document was merely to provide a preliminary indication from the point of view of an expert forensic accountant as to the quantum aspects of the claim as it was being formulated. Whilst the document does deal with other heads of claim than those in respect of which Mr Fairhurst was ultimately asked to provide expert evidence for the quantum trial, I do not consider that advice given thereby impinges upon Mr Fairhurst’s ability to give independent expert forensic accounting evidence for the purposes thereof. I hasten to suggest that it would not be unusual for an expert identified as a potential expert to provide an expert report for trial to be asked, at an earlier stage of the proceedings, to give a preliminary indication, or appraisal, of the issues that arise regarding quantum.

    50. I did not detect in the way that Mr Fairhurst gave his evidence, any partiality on his part. To the contrary, when I asked him a number of questions that were potentially inconsistent with, or disadvantageous to ARM’s case, he gave what I consider to be frank answers that did not necessarily assist ARM’s case, e.g. as to the potential effect on the profitability of ASS of there being a contingent element to its agreement with QHL.

    51. In these circumstances, I do not consider there to be any proper basis for ruling Mr Fairhurst’s evidence to be inadmissible as not being independent expert evidence.

    52. I found Mr Fairhurst to be a good witness, who had clearly grasped the quantum issues that arose … He gave clear and considered answers to the questions that were posed of him, and I consider that I am entitled to place very considerable weight and reliance on his expert evidence.

    Mr Fairhurst clearly impressed the judge. He demonstrated independence in his evidence for the court, despite having started from the position of an advisor to the claimant in the case. Key to this seems to have been his willingness to consider and concede appropriate points which were detrimental to the claimant’s case.


    When so many case reports show expert witnesses in difficulties or performing poorly, it is a pleasant change to be able to report on an expert who has excelled in meeting his duty to the court, having navigated some potentially difficult issues. It is worth reflecting on how he managed to achieve that by maintaining his independence and seeking a similar standard in one’s own expert witness work, particularly having initially reported as an expert advisor to one party.

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