The Ethics and Legality of Conferring with Another Party’s Expert

This paper was delivered at a Hemmant’s List seminar at its premises on 13 June. Mr Diehm KC is a former Bar Association vice-president and chair of Hemmant’s List, a professional service organisation for practising barristers. Mr Isdale is a former officer of the federal Law Reform Commission and now practices at the Queensland Bar. 

In a 2016 paper by Justice Henry – of the  Supreme Court of Queensland – his Honour observed:[1]

“The advantage likely to accrue to a potential cross-examiner in conferring in advance of a trial with an opponent’s expert is self-evident. Surprisingly, at least in my time at the Bar, it was very rare for my side’s expert to have been contacted by the other side’s lawyers with a view to them conferring with the witness.”

Anecdotally, some lawyers have expressed surprise that it could be legal, or ethical, to confer with another party’s expert. After all, in addition to providing evidence for proceedings, experts may be ‘brought into the fold’ and participate in confidential discussions. It may be considered that they owe duties of loyalty and confidence to the party that has first retained them.

In this article we consider whether it is legal, and ethical, to confer with another party’s expert. We conclude that the answer is ‘yes’ on both counts, despite some recent English case law which suggests that an expert may owe a fiduciary duty of loyalty to the party who has first retained them. We also explain how confidential information to which an expert becomes privy may be protected through the doctrine of legal professional privilege, and the equitable duty of confidence.

The legality of conferring with another side’s expert

The position in Australia

It is a well-known principle that there is “no property in a witness”.[2] With limited exceptions it is therefore open to any party to communicate with a person who will be called to provide evidence.[3] But does this principle apply to expert witnesses?

The English Court of Appeal considered this question in Harmony Shipping v Davis.[4] That case involved a hand-writing expert who inadvertently gave his opinion on the authenticity of a document to both sides of a civil dispute, on separate occasions. After realising he had done so, he declined to accept instructions from the latter firm of solicitors to give evidence, but was subsequently subpoenaed by them to do so. The question on appeal was whether the subpoena should be set aside. In the course of considering that issue, Lord Denning MR (with whom Waller LJ and Cumming-Bruce LJ agreed) said:[5]

“If an expert witness has been consulted by one side and has given his opinion to that side, can he thereafter be consulted and subpoenaed by the other side to give his opinion on the facts of the case? …

So far as witnesses of fact are concerned, the law is as plain as can be. There is no property in a witness. The reason is because the court has a right to every man’s evidence. Its primary duty is to ascertain the truth. Neither one side nor the other can debar the court from ascertaining the truth either by seeing a witness beforehand or by purchasing his evidence or by making communication to him. In no way can one side prohibit the other side from seeing a witness of fact, from getting the facts from him and from calling him to give evidence or from issuing him with a subpoena.”

Subject to two qualifications discussed later in this article (concerning legal professional privilege and the equitable duty of confidence), his Lordship concluded:[6]

“… it seems to me that an expert witness falls into the same position as a witness of fact. The court is entitled, in order to ascertain the truth, to have the actual facts which he has observed adduced before it and to have his independent opinion on those facts. … So it seems to me on principle that [the expert] can be subpoenaed. He can be seen beforehand and give a proof … and give evidence accordingly.”

Notably, the Court rejected an argument that there could be any express or implied contractual term prohibiting the expert from giving evidence for only the first party to retain them. Any such term would be “contrary to public policy and would not be enforced by the court”, on the basis that it is the “primary duty of the courts to ascertain the truth” and that duty is “not to be taken away by some private arrangement or contract”.[7] Further:[8]

“If an expert could have his hands tied by being instructed by one side, it would be very easy for a rich client to consult each of the acknowledged experts in the field. Each expert might give an opinion adverse to the rich man, yet the rich man could say to each, ‘Your mouth is closed and you cannot give evidence in court against me’.”

In summary, Harmony stands as authority for the “general principle” that “[t]here is no property in an expert witness as to the facts he has observed and his own independent opinion on them”.[9] It has been cited with approval by numerous courts in Australia, and it may be accepted to represent the law in this country.[10]

In our view, because there is no property in a witness, there is nothing unlawful in Australia about a witness conferring with and providing an opinion to a party other than the party who first retained them – and nor in a party seeking to elicit such an opinion or engage in such a conferral.

The position in England and Wales

The view we have expressed above may no longer hold in England and Wales. Despite the approval of Harmony in numerous judgments of English courts,[11] the position appears to have been complicated by a recent judgment of the Court of Appeal of England and Wales in Secretariat Consulting Pte Ltd v A Company.[12]That judgment appears to favour the view that an expert may owe a fiduciary duty of loyalty to a party who has retained it. Further, a contractual ‘no conflict’ provision can be enforced to prevent an expert from providing an expert opinion to another party.

Secretariat concerned companies from the Secretariat group providing expert quantum services to two different parties, one of whom was making a claim against the other, in construction arbitrations arising out of the same project.[13] In other words, Secretariat had begun providing similar expert services both for and against a claimant, in respect of the same or similar subject matter.[14]

At first instance an injunction was granted restraining Secretariat from providing services to the second company that had engaged it.[15] The primary judge did so on the basis that Secretariat “owed a fiduciary duty of loyalty … arising out of its engagement to provide expert services”, which prevented it from accepting an additional retainer from the other party.[16] The duty of loyalty was not satisfied simply by ensuring that confidentiality would be preserved, because a “fiduciary must not place himself in a position where his duty and his interest mayconflict”.[17] In so concluding, the primary judge rejected an argument that independent experts do not owe a fiduciary duty of loyalty to their clients by reason of the overriding duty owed to the court or tribunal in which the evidence is to be given.[18]

In the Court of Appeal, Coulson LJ (with whom Carr LJ, now Carr CJ, agreed) considered that it was not strictly necessary to consider whether a fiduciary relationship arose in order to dispose of the appeal.[19] Nonetheless, his Lordship made comments which indicated that the Court was favourably disposed towards the conclusion that an expert may owe fiduciary duties to an instructing party, despite an “absence of authority” on the point.[20] For instance, it was said that:[21]

“The fact that fiduciary duties are usually found to arise in settled categories of relationship, which have not hitherto been held to encompass the relationship between a professional expert and his or her client, does not mean that the possibility that a fiduciary duty of loyalty was owed in the present case should automatically be rejected. … It does not follow that, simply because there has never been a case in which such a duty was asserted and found, no such duty can exist.”

Further, that:[22]

“Depending on the terms of the retainer, the relationship between a provider of litigation support services/expert on the one hand, and his or her client on the other, may have one of the characteristics of a fiduciary relationship, namely a duty of loyalty or, to put it another way, a duty to avoid conflicts of interest.”

Lord Justice Males rejected the possibility, concluding that an “expert witness is not a fiduciary and does not owe fiduciary duties to his client”, but his Lordship did not explain the basis for that conclusion.[23] Nonetheless, his Lordship, along with the other members of the Court, rejected an argument that a fiduciary duty could not arise on account of it being in conflict with an expert’s overriding duty to the court.[24] According to Coulson LJ, that was because:[25]

“Where an expert witness is retained, it is likely to be, as it was in the present case, on terms that the expert will perform the functions specified in the CPR [Civil Procedure Rules]. The expert agrees with his client that he will perform the duties that he owes to the court. Thus there is no conflict between the duty that the expert owes to his client and the duty that he owes to the court.”

The basis on which the Court actually proceeded to resolve the appeal was contractual. Namely, the contract between Secretariat and the first party which had retained it included a ‘conflict of interest’ term, by which Secretariat confirmed it had no conflict of interest and would “maintain this position for the duration of [its] engagement”.[26] The Court considered that, by accepting the second retainer, Secretariat had breached that contractual obligation.[27]

Accordingly, the appeal was dismissed – with the consequence that the injunction granted by the primary judge (restraining Secretariat from providing expert services to the second party) remained in effect.[28]

In sum, Secretariat appears to support the position that – contrary to the position we have described as applying in Australia – an expert in England or Wales may be prevented by contract, and possibly by a fiduciary duty of loyalty, from conferring with or providing their expertise to a party other than the party who has first retained them.

A reflection on the current state of the law in England and Wales

We find the decisions in Harmony and Secretariat difficult to reconcile. Part of the difficulty arises from the absence of engagement by the latter decision with the former. Although there are a couple of references in Secretariat to Harmony, their Lordships seek to downplay the earlier decision by describing it as confined to its “peculiar facts”.[29]

In our respectful view, that description of Harmony is not consistent with what the Court of Appeal in that case described as the “question of principle”[30] or “general principle”[31] which it resolved – namely, that there is no property in a witness (including an expert).[32] The Court in Secretariat did not engage with the acceptance by many courts subsequently of that general principle,[33] nor explain how the views they reached are consistent with that principle.

We find it hard to accept that the views expressed in Secretariat could be consistent with the general principle of there being no property in a witness. If an expert were to owe a fiduciary duty of loyalty to a party who retained it, preventing them from providing an opinion to another party, that would be an outcome in which one party may be broadly described to have achieved ‘ownership’ of an expert and their expertise, contrary to the reasoning in Harmony.

Further, the majority in Secretariat did not address the view in Harmony that a contractual term that prohibits an expert from providing expert services to another party, or being called to give expert evidence by another party, would be “contrary to public policy”.[34] Inconsistently with that view, in Secretariat the Court gave effect to a contractual restraint to avoid conflicts of interest, which the Court considered prevented the expert from providing expert services to another party.[35] Males LJ said that the public policy principle did not arise but, with respect, did not convincingly engage with the rationales for that principle as outlined in Harmony, nor provide a convincing explanation as to why the principle was not applicable in Secretariat.[36] 

The inconsistency of Secretariat with the public policy reasoning in Harmony is evident in the fact that the approach in Secretariat would allow for precisely the outcome that Denning LJ and Waller LJ considered intolerable; that a rich client could consult each acknowledged expert in the field and say to each, “Your mouth is closed and you cannot give evidence in court against me” (by reason of a contractual, or fiduciary, duty to that party).[37]

Assuming that Secretariat represents the law in England and Wales, a question arises as to whether it may, in future, be followed in Australia.

A reflection on whether Secretariat should be followed in Australia

Apart from the difficulties we have already identified with Secretariat, we consider that there are strong additional reasons why courts in Australia should be persuaded not to adopt the reasoning or conclusions of that case. In particular, that is because:

1. as observed by Mason J (as his Honour then was) in relation to fiduciary relationships in Hospital Products: “[t]he critical feature of these relationships is that the fiduciary undertakes or agrees to act for or on behalf of or in the interests of another person”.[38] Under rules of court in Australian jurisdictions, experts are proscribed from being an advocate for a party and must act impartially.[39] In those circumstances, it cannot be said that the relationship between an expert and a party who retains them is one in which the expert has undertaken or agreed to “act for or on behalf of or in the interests of” that party;
2. experts do not merely owe an ‘overriding’ or ‘paramount’ duty to the Court or arbitral tribunal, such as may be consistent with co-existing duties of loyalty to a party retaining them, the latter giving way only in the case of a conflict (as considered in Secretariat).[40] Instead, they owe duties to provide “independent assistance to the Court” that “should be, and should be seen to be, the independent product of the expert”.[41] It is difficult to see how such duties to provide independent assistance could possibly co-exist with any fiduciary, or contractual, duty to act with ‘loyalty’ to any particular party;[42]
3. contrary to the view expressed in Secretariat, there is arguably no conflict of interest if an expert retained by one party provides their expertise to another. That is because the expert owes an undivided duty to the Court to be independent and impartial in the provision and preparation of their expert evidence. There can be no conflict of interest if no duty to act in the interests of a particular party was owed in the first place. The conclusion in Secretariat is premised on the notion that an expert owes a duty to favour the interests of one party over another – but the Court reached that conclusion on the basis of a contractual ‘no conflicts’ clause,[43] indicating circularity in the reasoning deployed;[44] and  
4. in Secretariat, the Court drew some support for its views from the UK Supreme Court’s decision of Jones v Kaney, on the basis that that decision draws “a close comparison between expert witnesses and advocates” and indicates that there is no necessary conflict between a paramount duty to a court and a duty of loyalty to a party.[45] The comparison is inapt for the reasons outlined in the preceding paragraph and accompanying footnotes. However, in addition, that decision – which abolished an expert’s immunity from suit – has not been followed in Australia.[46] In those circumstances, such support as may have been gained in Secretariat from that decision, is unlikely to have the same traction in Australia.

In conclusion, on the basis of current authority in Australia – and what we consider to be the better view – the decision of Harmony remains good law. So too the conclusion that flows from it: that it is entirely lawful for a party to confer with and obtain evidence from an expert who has already been engaged by another party.

There may be an argument that the position is, and should, be different in the case of an ‘expert’ who performs the role of an advisor of consultant. We consider that is likely correct, so long as this ‘expert’ does not provide any evidence for use in court. Arguably, an expert who at any point in time has acted in an advisory or consultancy role for a party may, by virtue of such, have lost the ability to be “independent”, depending on the precise nature of that role, and would therefore be precluded from giving expert evidence. As observed by Mullighan J in Duke Group Ltd (in liq) v Pilmer & Ors:[47]

“In some cases the state of lack of independence and the consequence of unreliability may not be readily apparent and may not even be appreciated by the witness. Working ‘in the team’ can have the effect of the witness subsuming the work, attitudes and opinions of others, even unwittingly with an obvious contaminating effect.”

In the remainder of this article we explore the ethical and professional rules which bear on the propriety of engaging or conferring with ‘another party’s’ expert,[48] and how the law may limit the content of any such engagement or conferral, through the doctrine of legal professional privilege or the equitable duty of confidence.

The ethics of conferring with another side’s expert

The ethics of conferring with ‘another party’s’ expert is inevitably informed by the legal principles we have already, in part, discussed. In particular, it is informed by the rules of court which govern the role of experts in a proceeding. For example, in New South Wales, Victoria, and in the Federal Court of Australia, rules of court relevantly provide that:[49]

“An expert witness is not an advocate for a party and has a paramount duty, overriding any duty to the party to the proceedings or other person retaining the expert witness, to assist the court impartially on matters relevant to the area of expertise of the witness.”

In Queensland, rule 429F of the Uniform Civil Procedure Rules is less fulsome, but nonetheless makes clear that the expert “has a duty to assist the court” and is “not an advocate for a party to the proceeding”.[50]

In our view, such rules of court are consistent with the conclusion that parties and experts are free to confer with one another. Indeed, conferral is consistent with an expert assisting the court impartially on matters relevant to their expertise, by providing the benefit of their expertise (where it is sought) to more than only the first party to retain them.

There is a strong argument that it would be unethical for an expert to decline to confer or provide their expertise to a party based on an alleged duty to one party only. Notably, in the New South Wales Supreme Court’s decision of R v Fleming, Wilson J was critical of an expert who had “refused to discuss her evidence or subject of expertise” with opposing counsel and solicitors.[51] Her Honour said:[52]

“This refusal does not accord with the conduct expected of an independent expert, and has again seriously hindered the accused’s ability to understand and meet the evidence of the professor.

The Expert Witness Code of Conduct imposes on an expert witness an overarching duty to assist the court impartially. A refusal to engage with the accused’s lawyers must call into question the independence of Professor Smith’s professional judgment. Her refusal … must raise at least the possibility that the witness may be seen as aligned with one party to the proceedings.”

Finally, we consider that the conclusion that it is ethical to confer with another party’s expert gains some indirect support from the Australian Solicitors Conduct Rules, rule 23.1 of which provides that:

“A solicitor must not take any step to prevent or discourage a prospective witness or a witness from conferring with an opponent or being interviewed by or on behalf of any other person involved in the proceedings.”

There is no reason to believe that the same rule is not equally applicable in the case of a prospective or actual expert witness. That rule would appear to forbid a solicitor from seeking to restrain an expert (on their clients’ behalf) from conferring with or providing the benefit of their expertise to another party – as occurred in Secretariat by way of an application for an injunction. The rule would also prohibit a solicitor from preparing a contract on behalf of a client that purported to prohibit, or would have the effect of prohibiting, a prospective expert witness from conferring with another party or their lawyers.

Rule 73 of the Barristers’ Conduct Rules (Qld) is to the same effect.

Limits on what an expert may say to another party

To the extent the law in Australia does impose limits on what an expert may say to a party other than the party that has retained them, those limits are set by the doctrines of legal professional privilege and the equitable duty of confidence.[53]

As observed by Johnson J in Rapid Metal Developments, “the authorities make it clear that the expert witness is not entitled to divulge confidential or privileged information” (including in “pre-trial communications”).[54]

Legal professional privilege

Legal professional privilege protects the “confidentiality of certain communications made in connection with giving or obtaining legal advice or the provision of legal services, including representation in proceedings in a court”.[55] The test is whether the communications were made for the “dominant purpose” of giving or obtaining such advice or services.[56]

As observed by the New South Wales Court of Appeal in Fagan v New South Wales (per Beazley JA, Spiegelman CJ and Santow JA agreeing), the principle that there is “no property in a witness” “has to operate in conjunction with other principles, including the principle of legal professional privilege”.[57] 

Legal professional privilege extends to communications by some third parties with a person’s legal advisers. As observed in Fagan:[58]

“In the case of third party communications, the specific purpose of the privilege is to enable the person to prepare properly a case for litigation untrammelled by a fear that his/her case will be disclosed to the opposing party, other than in accordance with the relevant rules of Court.”

To the extent an expert is in receipt of material which is subject to legal professional privilege – such as concerning a party’s litigation strategy – that material may be privileged.[59] However, not all communications received by an expert from a party will be so privileged. Apart from the general requirements outlined above:

1. There is clear authority to the effect that “documents used by an expert to form an opinion are not the subject of legal professional privilege, whether or not they emanated from the party claiming privilege”; further, that the “opinion itself is not privileged”.[60]
2. Issues of waiver may arise. For example, in the recent case of Enkelmann v Stewart, the Queensland Court of Appeal held that a failure by opposing counsel to object to cross-examination of an expert, who was asked about matters discussed at a meeting with the appellants’ legal advisers, meant that privilege in relation to those communications had been waived.[61]  Further, the disclosure of privileged information to an independent expert witness (as opposed to an expert retained to provide partial advisory services) may, at least in some circumstances, be conduct that is “inconsistent with the maintenance of the confidentiality which the privilege is intended to protect”, and thereby amount to a waiver.[62]
3. Rules of court may abrogate the privilege. For example, rule 212(2) of Queensland’s Uniform Civil Procedure Rules 2011 expressly provides that “[a] document consisting of a statement or report of an expert is not privileged from disclosure”. However, there may be dispute about the limits of such abrogation, and any abrogation may be read narrowly on the basis that legal professional privilege is an “important common law immunity”.[63]

Equitable duty of confidence

Equity may also impose limits on the information that an expert is at liberty to disclose to another party (and other persons generally). That will be the case if the information has the “necessary quality of confidence about it” and has been “imparted in circumstances importing an obligation of confidence”.[64]

For example, if an expert were to come into possession of information from their instructor about ‘trade secrets’ unrelated to the subject matter of their expertise, such information is likely to be confidential.[65] If the circumstances in which that information was received were such that a reasonable person would have realised that it was being given in confidence, then this “should suffice to impose upon him [the expert] the equitable duty of confidence”.[66]

However, a key limitation is that matters in dispute between parties, and on which the expert is to provide an opinion, are very unlikely to have the necessary quality of confidentiality. As observed by Williams J (as his Honour then was) in Commonwealth Bank of Australia v Cooke, there is a general principle that: [67]

“there is no property or confidentiality in the knowledge of an independent witness of matters relevant to an issue between the parties”.

His Honour suggested that different considerations may apply if a witness is “not independent but rather an expert consultant” to “one party to the litigation”, since a “relationship of confidentiality” may exist in such a circumstance.[68] However, we read his Honours’ comments as applying only where an expert is used as a consultant or advisor, and not an expert whose opinion will be adduced in evidence. In the latter case, the expert must be ‘independent’ for the reasons discussed earlier in this article. 

Conclusion

In this article we have explained why it is entirely lawful, and ethical, to confer with another party’s expert witness. It may be done and often may usefully be done for the purpose of understanding the matters on which the expert may give evidence, or to additionally seek the benefit of their expert opinion.

Although expert witnesses may be retained by individual parties, in circumstances which might ordinarily invite the view that a ‘duty of loyalty’ is owed, we consider that any such notion of loyalty is displaced by the duty of expert witnesses to be impartial and not an advocate for any party.

However, experts are not entirely at large on the matters they may disclose to other parties. In particular, they must not disclose communications which are subject to legal professional privilege or an equitable duty of confidence. As discussed, such protected communications do not include matters on which an expert has been asked to form a view for the purposes of providing evidence.

In conclusion, for a party who seeks to fully understand the case they may be required to make or meet, there is much to be gained by conferring with another party’s expert witness – and nothing wrong in doing so. 

[1] Justice Henry, ‘Expert Evidence: A view from the bench’ (2016, speech to the Australian Lawyers Alliance National Conference) [25] <https://archive.sclqld.org.au/judgepub/2016/henry221016.pdf>.

[2] Fagan v State of New South Wales [2004] NSWCA 182, [70] (per Beazley JA, Spiegelman CJ and Santow JA agreeing).

[3] State of New South Wates v Jackson [2007] NSWCA 279, [33] (per Giles JA, with whom Mason P and Beazley JA agreed).

[4] Harmony Shipping Co SA v Davis and others [1979] 3 All ER.

[5] Ibid 180.

[6] Ibid 181.

[7] Ibid 182.

[8] Ibid 182.

[9] Ibid 182. Lord Denning described the question before the court as a “question of principle” (at 180), and provided his answer to the question in the passage quoted. Waller LJ likewise said that “the general principle must be that no party has any property in a witness” and that there was no difference between a witness of fact and an expert witness “as a matter of general rule” (at 182).

[10] For example, Interchase Corporation Limited (in liq.) v Grosvenor Hill (Queensland) Pty Ltd (No 1) (1999) 1 Qd R 141, 146-8 (per Pincus JA, with whom de Jersey J agreed); State of New South Wales v Jackson [2007] NSWCA 279, [33] (per Giles JA, with whom Mason P and Beazley JA agreed). Most recently, see application in Wang v Yu [2023] NSWSC 1182, [166] (Meek J): “… there is no ‘property’ in a witness and one side cannot ‘prohibit the other side from seeing a witness of fact, from getting the facts from him and from calling him to give evidence or issuing him with a subpoena’” (citing Harmony).

[11] For example, Qatar Investment & Project Development Holding Co v John Eskenazi Ltd [2022] EHWC 3022, [186] (per Jacobs J); A Lloyd’s Syndicate v X [2011] EWHC 2487, [30] (Teare J).

[12] Secretariat Consulting Pty Ltd & Ors v A Company [2021] 4 WLR 20.

[13] Ibid [2] (per Coulson LJ).

[14] Ibid (per Coulson LJ).

[15] A Company v X [2020] BLR 433; [2020] EWHC 809 (TCC), [66].

[16] Ibid [66] (per O’Farrell J).

[17] Ibid [60]-[61].

[18] Ibid [39], [53] (per O’Farrell J).

[19] Secretariat Consulting Pty Ltd & Ors v A Company [2021] 4 WLR 20, [65] (per Coulson LJ).

[20] Ibid [3].

[21] Ibid [59].

[22] Ibid [66].

[23] Ibid [104] (per Marles LJ).

[24] Ibid [49] (per Coulson LJ); [106]-[110] (per Marles LJ); [125] (per Lady Justice Carr).

[25] Ibid [49] (per Coulson LJ); [125].

[26] Ibid [13] (Coulson LJ).

[27] Ibid [99] (Coulson LJ, Carr LJ agreeing); [118]-[124] (Males LJ).

[28] Ibid [100] (Coulson LJ); [124] (Males LJ); [125] (Carr LJ).

[29] Ibid [111] (Coulson LJ, Lady Justice Carr agreeing); [55] (Males LJ).

[30] Harmony Shipping Co SA v Davis and others [1979] 3 ALL ER, 180 ( Lord Denning).

[31] Ibid 182 (Waller LJ).

[32] Ibid 182 (per Lord Denning, with whom Cumming-Bruce LJ agreed, and Waller LJ).

[33] For example, Qatar Investment & Project Development Holding Co v John Eskenazi Ltd [2022] EHWC 3022, [186] (per Jacobs J); A Lloyd’s Syndicate v X [2011] EWHC 2487, [30] (Teare J).

[34] Ibid 182 (per Lord  Denning, with whom Cumming-Bruce LJ agreed, and Waller LJ).

[35] Secretariat Consulting Pty Ltd & Ors v A Company [2021] 4 WLR 20, [82]-[98] (per Coulson LJ, with whom Carr LJ agreed); [119]-[124] (per Marles LJ).

[36] Ibid [107]. His Lordship said that: “The principle of public policy to which Lord Denning MR (but not Waller or Cumming-Bruce LJ) referred in Harmony Shipping, that (subject to privilege) a contract not to give evidence on a matter within the expert’s knowledge would be unenforceable, simply does not arise. If an expert does not accept instructions from a prospective client when he has a conflict, there will be no question of preventing him from giving evidence on matters within his knowledge as he will not acquire the knowledge in the first place.” However, in Secretariat the respondent had already accepted instructions to act for both parties, and was sought to be restrained from acting for the latter party, including on the basis of contract. It is not clear why his Lordship considered that the principle against the validity of such a contractual constraint was not applicable in those circumstances. Further, it is not correct to imply that the public policy view in Harmony was held by Lord Denning alone; Waller LJ at 182 expressly approved of these observations on that topic (relating to the possibility otherwise of a rich person being able to “buy up all the possible experts”. Further, although Cumming-Bruce LJ did not specifically advert to the public policy reasoning himself, he expressed general agreement with the reasons of Lord Denning and Waller LJ by stating “I agree” and adding only limited comments on a few matters. 

[37] Harmony Shipping Co SA v Davis and others [1979] 3 ALL ER, 182.

[38]  Hospital Products Ltd v United States Surgical Corporation (1984) 156 CLR 41, 96-7.

[39] E.g. Uniform Civil Procedure Rules 2005 (NSW) Schedule 7, rule 2; Supreme Court (General Civil Procedure) Rules 2015 (Vic) Form 44A – Expert witness code of conduct, rule 2; Federal Court of Australia ‘Expert Evidence Practice Note (GPN-EXPT) (25 October 2016). Similar rules pertain in other jurisdictions.

[40] Secretariat Consulting Pty Ltd & Ors v A Company [2021] 4 WLR 20, [49] (per Coulson LJ, with whom  Carr LJ agreed);

[41] National Justice Compania Naviera SA v Prudential Assurance Co Ltd, The Ikarian Reefer [1993] 2 Lloyd’s Rp 68 (per Creswell J); see approval in, for example, Sydney South West Area Health Service v Stamoulis [2009] NSWCA 153, [202](Ipp JA, with whom Beazley and Giles JJA agreed), and in Wood v R (2012) 84 NSWLR 581, [719] (per McClellan CJ at CL, with whom Latham and Rothman JJ agreed).

[42] In Secretariat, Coulson LJ sought to analogise the position of an expert with that of an “advocate” (i.e. a barrister), on the basis that: “Each undertakes a duty to provide services to the client. In each case those services include a paramount duty to the court and the public, which may require the advocate or the witness to act in a way which does not advance the client’s case” – at [50]. However, with respect, the analogy in inapt; a barrister or advocate, whilst owing an ‘overriding’ or paramount duty to the court, could not fairly be said to owe a duty to be ‘independent’ or ‘impartial’, as is expected of an expert. To the contrary, the duty of an advocate or barrister is to advocate on behalf of a particular party (not to be impartial or independent) – albeit within the confines of ethical and professional rules.

[43] Secretariat Consulting Pty Ltd & Ors v A Company [2021] 4 WLR 20, [82]-[101] (per Coulson LJ, with whom Carr LJ  agreed); [119]-[124] (per Males LJ).

[44] The reasoning is circular because if an expert is required to be impartial or independent, then their providing that expertise to another party involves no breach of a ‘no conflict of interest’ requirement (because they never undertook to act in the interests of one party in the first place).  

[45] [2011] UKSC 13. See references in Secretariat Consulting Pty Ltd & Ors v A Company [2021] 4 WLR 20 at [27] (quoting the primary judge), [56], [61] (per Coulson LJ, with whom Carr LJ agreed), [110] (per Males LJ) and [125] (per Carr LJ).

[46] See, e.g. Young v Hones [2014] NSWCA 337, [13]-[16] (per Bathurst CJ). See also Hastwell v Parmegiani [2023] NSWSC 1016, [62] (per Cavanagh J). Leave to appeal in relation to the issue of witness immunity was granted in Hastwell v Parmegiani [2024] NSWCA 55, [33] (per Gleeson and Kirk JJA), but the appeal in this regard has not yet been resolved at the time of writing.

[47] (1998) 144 FLR 1, 147. In that case, Mullighan J considered that the relevant expert valuer’s independence had not been lost, despite the advisory work he had also performed: at 148 (“I have no hesitation in accepting his evidence”).

[48] Although referring to ‘another party’s’ expert is common, that language is somewhat inconsistent with the requirements of impartiality and independence. We use the term as a short-hand for an expert retained by a party to give evidence.

[49] Uniform Civil Procedure Rules 2005 (NSW) Schedule 7, rule 2; Supreme Court (General Civil Procedure) Rules 2015 (Vic) Form 44A – Expert witness code of conduct, rule 2; Federal Court of Australia ‘Expert Evidence Practice Note (GPN-EXPT) (25 October 2016).

[50] Uniform Civil Procedure Rules 2011 (Qld) r 429F.

[51] R v Wilson [2023] NSWSC 560, [70].

[52] Ibid [70]-[71].

[53] That is consistent with the view of Denning LJ in Harmony ([1979] 3 All ER 177), where his Lordship said at 181 that: “Many of the communications between the solicitor and the expert witness will be privileged. They are protected by legal professional privilege”, or “the rule protecting information given in confidence”. But “[s]ubject to that qualification, it seems to me that an expert witness falls into the same position as a witness of fact.”

[54] Rapid Metal Developments (Australia) Pty Ltd v Anderson Formrite Pty Ltd & Anor [2005] WASC 255, [150] (Johnson J). Further, at [151]: “a court will not intervene to prevent an expert witness from giving evidence on behalf of another party but will take appropriate action to prevent the witness from disclosing confidential or privileged information”.

[55] Esso Australia Resources Limited v The Commissioner of Taxation (1991) 201 CLR 49, [35] (Gleeson CJ, Gummow and Gaudron JJ).

[56] Ibid [62].

[57] [2004] NSWCA 182, [70].

[58] [2004] NSWCA 182, [71].

[59] ASIC v Southcorp Limited (2003) 46 ACSR 438, [21] (Lindgren J): “Ordinarily the confidential briefing or instructing by a prospective litigant’s lawyers of an expert to provide a report of his or her opinion to be used in the anticipated litigation attracts client legal privilege”; and “Copies of documents, whether the originals are privileged or not, where the copies were made for the purpose of forming part of confidential communications between the client’s lawyers and the expert witness, ordinarily attract the privilege” (citing numerous authorities in respect of each proposition).

[60] Interchase Corporation Limited (in liq.) v Grosvenor Hill (Queensland) Pty Ltd (No. 1) (1999) 1 Qd R 141, 148 (Pincus JA, with whom de Jersey J agreed); see also Thomas J at 162.

[61] Enkelmnann & Ors v Stewart & Anor [2023] QCA 155, [38]-[43].

[62] Mann v Carnell (1999) 201 CLR 1, [29] (per Gleeson CJ, Gaudron, Gummow and Callinan JJ).

[63] Ibid [23]-[24].

[64] Coco v A N Clark (Engineers) Ltd [1969] RPC 41, 47 (Megarry J).

[65] See e.g., Ansell Rubber Co Pty Ltd v Allied Rubber Industries Pty Ltd [1967] VR 37, 50 (Gowans J), outlining factors to be considered in determining whether given information constituted a ‘trade secret’ subject to a duty of confidence.

[66] Coco v A N Clark (Engineers) Ltd [1969] RPC 41, 48 (Megarry J).

[67] [2000] 1 Qd R 7, [30].

[68] Ibid.