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Assisting the court or tribunal

Assisting the court or tribunal

One of the primary purposes of expert evidence is to assist the court or arbitral tribunal in its reasoning and decision-making process on matters that are within the expert’s expertise. Legal and arbitral processes often have differing requirements of expert evidence, depending on the geographical location, nature and format of the proceedings. This article explores ways in which, in general terms, a party appointed expert can provide assistance to a court or tribunal in the context of construction disputes.

Ordinarily, expert evidence in construction disputes is independent opinion evidence, as distinguished from factual evidence, and is usually contained in written reports and/ or statements included as part of the parties’ submissions. That independent opinion evidence may be presented and tested in court or arbitration proceedings.

The expert’s primary duty is to the court1 or tribunal, but, as established in the case of Jones v Kaney2, the expert also has a duty to his or her client not to be negligent.

Author: Tom Comerford, Quantum Expert and Driver Trett Chief Operating Officer

The admissibility of the expert’s evidence

The admissibility of evidence will, in many cases, be governed by the applicable rules of evidence, be at the tribunal’s discretion or be by agreement. These are likely to limit what is presented as evidence. Generally, expert evidence requires leave of the court to be presented3, albeit this differs in the case of institutional procedural rules4 in arbitration.

The Civil Procedure Rules (‘CPR’) Part 35.4 requires, amongst other things, the court’s permission to call an expert or put in evidence the expert’s report. The directions order or procedural order is where the court or tribunal typically conveys the details of the expert and other evidence that will be allowed and these may specify the issues which the expert should address. Those issues will logically relate to the disputed issues and the parties’ positions in relation to those. The expert does not decide the disputed facts or the law (including contractual liabilities or obligations).

The expert’s opinion evidence can assist the court or tribunal in various ways, sometimes in the understanding of the factual evidence, particularly in the case of specialist technical matters or, by setting out the facts, literature, materials or anything else that the expert has relied on in forming their opinions, in order for the court or tribunal to make findings of fact. In other instances, such as in complex factual situations, where there may be large amounts of data, for example in construction disruption disputes, depending on how the evidence is presented, the expert often assists in effectively marshalling, distilling and communicating the facts as part of the rationale for his or her opinion.

The expert’s credentials

To be capable of being of assistance to the court or tribunal it is expected that, ordinarily, experts will have either, or a combination of, relevant education, knowledge or experience in their field of expertise. The 2011 Law Commission report on ‘Expert Evidence in Criminal Proceedings in England and Wales’ set out four requirements relating to the admissibility of expert evidence.

This included, under the heading of ‘Relevant Expertise’, that the expert must have the relevant experience, in that the individual “has acquired by study or experience sufficient knowledge of the subject or experience to render his [or her] opinion of value”. In his Sir Michael Davies Lecture to the Expert Witness Institute in June 2015, Sir Vivian Ramsey noted that whilst ‘…that was said in the context of criminal proceedings, the same could be said in terms of civil proceedings.’

The expert also needs to have knowledge of the standards that are to be expected of them. Following the common law duties arising from the Ikarian Reefer5 case, the Ministry of Justice provided rules, directions and guidance as to the standards with which experts are expected to comply, in the following:

  1. Civil Procedure Rules Part 35 - Experts and Assessors6
  2. Practice Direction 35 - Experts and Assessors7
  3. Civil Justice Council’s (‘CJC’) Guidance for the instruction of experts in civil claims8

Whilst these are only mandatory in litigation, they may also be incorporated in bespoke arbitration rules, or by the agreement of parties to the arbitration. In some arbitration proceedings, particularly where the institutional rules are limited on prescriptive details as to party-appointed experts, it may be the case that the Chartered Institute of Arbitrator’s ‘Protocol for the Use of Party-Appointed Expert Witnesses in International Arbitration’ or the ‘IBA Rules on the Taking of Evidence in International Arbitration’ might apply. In other cases, local laws may well apply, but in any event, it is important that the expert is aware of these rules, directions, guidance notes and protocols, and complies with them.

In addition, experts may also be subject to the codes, practice statements and guidance notes of the professional bodies of which they are members, such as:

  1. The Academy of Experts’ Code of Practice for Experts.
  2. The Expert Witness Institute Code of Professional Conduct and Practice.
  3. The RICS Practice Statement and Guidance Note - Surveyors Acting as Expert Witnesses 4th Edition amended 2020.
  4. The RIBA Code of Professional Conduct and Guidance Notes 2019.
  5. The ICE Code of Professional Conduct 2014.

The expert process

A comprehensive understanding of the duties of an expert, the rules applicable and the standards required of the expert will be invaluable in navigating the steps in proceedings9 that a party-appointed expert may encounter10, which could include11:

  1. Preparation and subsequent exchange of reports, including answers to written questions arising.
  2. Meeting of experts12.
  3. Joint reports/statements.
  4. Supplemental reports.
  5. Presentation and testing of opinion evidence at the hearing or trial. 

The expert's report

What constitutes a report that helps the court or tribunal will vary depending on the complexities of the dispute, and be particularly so in some technical matters. In the case of Weatherford Global Products v Hydropath & Ors [2014] EWIHC 2275 (TCC), the judge made a criticism that:

“There seemed to be a belief that the judge was a specialist electronics and electrical engineer who would understand, without any explanation, precisely how the technology worked, how the alleged deficiencies came about, how the various suggested fixes might work, how the experiments were to be understood and how the final device… worked. Lawyers and experts need to explain if necessary in words of one syllable all these matters.”

The above quote was included in James Bowling’s13 article in The Academy of Experts’ The Expert and Dispute Resolver, Winter 2014 edition, where he went on to give some useful guidance on how to prepare an expert report, as follows: 

“…report writing is a skill which can be learned - but only by really hard work to identify, appreciate and understand the key issues, marshal them into the right order, and then write a report which addresses them in a logical way. If this is done right, you will find that the report, in effect, writes itself. The really hard thinking comes in identifying and crystallising the right approach in the first place. Once that analysis has been done, your experience and qualifications should enable you to write a clear, concise answer. Remember, if you don’t start by identifying the right questions, you won’t get to the right answers.”

In addition to the rules, directions, guidance notes, protocols and professional standards referred to previously, the expert’s report should address the requirements of his or her instructions, within any budgetary constraints, and include references to the information that the expert relies on (providing copies of such where necessary).

The opinions arrived at should be supported by the facts and/or the expert’s reasoning.

The CJC’s Guidance helpfully provides detailed best practice in relation to the content of expert reports, including where a sequential exchange of reports is required14.

Practice Direction 35, paragraph 3.2, recognises that there may be a range of opinions. This is not uncommon in many construction cases, given the nature and extent of the matters in dispute. This often requires the expert to give opinions based on alternative assumed facts for the assistance of the court or tribunal. Practically, and in terms of proportionality of cost, in complicated cases, such as in a delay analysis where there may be different factual outcomes, this can be very difficult. 

Exchange of expert reports and meeting(s) of experts

The preparation of a well-structured and compliant report, adopting the guidance above, that clearly deals with the issues, should result in a focused document, more readily capable of comparison, which can then be exchanged on an ‘open’15 or ‘without prejudice’16 basis. Such a report should assist in the next step of the expert process, that being a constructive ‘without prejudice’17 meeting of experts to further agree points and narrow the differences18. Meetings of experts in court proceedings, without a prior exchange of reports, is not uncommon, albeit it will still be necessary for the expert to have undertaken a number of the steps, he or she would have done prior to the drafting of the report, in any event.

Mindful of any issues the court or tribunal may have specified to be discussed and any agreed agenda, at the meeting, the experts may agree on, amongst other things, the issues, terminology, methodology and the points that they concur on. By way of example, the early agreement of the methodology for a delay analysis, or a disruption claim, can have significant time and cost advantages. Practice Direction 35, paragraph 9.2, sets out what is required from the experts meeting in the form of a statement that identifies the extent of agreement, points of and reasons for any disagreement, actions if any to be taken to resolve any outstanding points of disagreement, and any further material issues not raised and the extent to which they are agreed.

If the experts reach agreement on points or issues, then that is expected to hold significant evidential weight. Given that the experts’ joint statement is most likely to be presented to the court or the tribunal, in my experience, it is important that this statement is clearly written and accurately records the experts’ positions in order to be of the greatest assistance.

In some cases, supplemental reports may be required on the points that remain in disagreement and the same principles as set out previously in relation to the experts first report should be adopted.

The opinions contained in individual reports and joint statements, particularly as to the points in disagreement, may be adopted and tested at the court trial or tribunal hearing. This can be in the form of questions from the judge or tribunal, cross examination, concurrent witness evidence or re-examination.

The expert needs to be fully prepared for this, and be able to respond to questions in a calm, considered, clear and unambiguous manner.

How not to assist the court or tribunal

Inevitably, there are many ways in which an expert does not assist the court or tribunal, examples of which can include:

  1. Accepting an appointment on an incentive-based fee.
  2. Lacking in independence and/or objectivity.
  3. Stepping outside the expert’s area of expertise.
  4. Acting as advocate.
  5. Selective use of evidence.
  6. Failure to test the validity of materials provided to them.
  7. Accepting instructions from lawyers that will not knowingly result in a credible report.
  8. Undertaking poor analysis.

There have been numerous published accounts of where experts have fallen short of their duty to assist the court or tribunal which I do not repeat here, but which serve as a continuous reminder of the need for the expert to act in an objective, independent and impartial manner.


In summary, a party-appointed expert should fully understand the duties of an expert, and the rules and protocols that are applicable to the proceedings, and the standards that are to be expected of them.

The expert is expected to have either, or a combination of, the relevant education, knowledge or experience of the issues in dispute. With these attributes, the expert should produce a report that is compliant, assists the court or tribunal in understanding the facts, is logically structured and addresses the key issues in a coherent, concise and reasoned manner.

The expert’s meetings play an important part in agreeing points and narrowing the differences, thereby assisting the court or tribunal in focusing on the matters that it needs to address. Clear and well drafted joint statements are important in this process, and experts should be prepared to invest time in developing those statements.

In the event that the dispute continues to a court trial or tribunal hearing, then the expert needs to be fully prepared for such. The expert must be able to respond to questions and cross-examination in a calm, considered, clear and unambiguous manner that assists, where possible, the court or tribunal in its understanding of the facts and in its decision-making process.

In short, a good expert can be of assistance to the court or tribunal, by providing written and oral clarity on matters within the expert’s field of expertise, working with other experts to narrow differences, and assisting the court to understand the facts on disputed issues in reaching its decision.

Originally written as part of the Driver Trett Digest, issue 24. To view the publication, please visit: www.driver-group.com/digest-compendium

In the context of this article the references to ‘court’ or ‘litigation’ are references to the courts of England and Wales.
Jones v Kaney [2011] UKSC 13.
This is not the case in Scotland, for example.
For example, see Article 20 of the LCIA Arbitration Rules 2021, or Article 27 UNCITRAL Arbitration Rules to name but a few.
The Ikarian Reefer [1994] 2 Lloyds Rep 68.
In arbitration proceedings these will differ between memorials (submissions and witness/expert evidence filed together) or pleadings (submissions filed in advance of witness/expert evidence) and, arbitration proceedings differ from court proceedings.
10 These will differ in the pre-action stages. 
11 In some arbitration proceedings, the procedure may be agreed by the parties, or as the tribunal determines appropriate.
12 Ordinarily held on a ‘without prejudice’ basis, in that the content of the discussions is not referred to unless agreed by the parties.
13 James Bowling is a barrister at 4 Pump Court and former editor of the ‘Cases’ for the TEDR.
14 See paragraphs 48 69 of the Civil Justice Council’s Guidance for the instruction of experts in civil claims.
Disclosed to the tribunal and used in evidence.
16 Only disclosed to the parties and experts and not the tribunal.
17 Confidential and not disclosed to the tribunal.
18 The expert’s role is not to settle the case.


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