News Criminal Defence 15th Oct 2019

A Cautionary Tale for Experts by Narita Bahra QC


The original Guidance Booklet for Experts was published by the Crown Prosecution Service and the Association of Chief Police Officers in May 2010 (‘the ACPO Guidance’) and endorsed by the then Director of Public Prosecutions Keir Starmer QC. In October 2015, the most recent Criminal Procedure Rules (‘CrimPR’) were introduced.

The importance of this guidance has become key as a result of a multi-million pound fraud collapsing (R v Sulley – May 2019) due to expert witness failings here and here.

The CPS have therefore, updated this important and useful document, which all practitioners should read before instructing or challenging expert witnesses.

What are the material changes to the guidance?

The guidance’s focus still remains on emphasising the expert’s duty to retain, record and reveal. It also explains, in stark terms, the serious consequences of failing to comply with those obligations.

The principles of retain, record and reveal are summarised in the ACPO Guidance as follows:

  1. Duty to retain – a duty to retain everything, including physical, written and electronically captured material, until otherwise instructed.
  2. Duty to record – a duty to commence making records from the time of instruction and to continue to make records for the entire period in which the expert is involved. Section 4.2.2 of the ACPO Guidance makes it clear that, at a minimum, what must be recorded is the collection and movement of items; the examination of materials; and oral and other communications in respect of the investigation.
  3. Duty to reveal – a duty to make the prosecution team aware of all that the expert has recorded and all of the material in the expert’s possession in respect of the investigation.

The real material change is that the 2019 updated guidance now firmly acknowledges the importance of applying the Criminal Procedure Rules.

It has always been essential that the Criminal Procedure Rules, Part 19 are read in conjunction with the Practice Direction at CPD V Evidence 19A to C. It should be noted that the recent amendment to the CrimPR was on 1 April 2019, when an obligation was imposed, via the insertion of para 19A.7 of the Practice Direction, on a party introducing expert evidence to ascertain and disclose information that has the potential to undermine the reliability or credibility of their expert evidence. The guidance makes it clear that the type of information contemplated includes, amongst other things, previous adverse judicial comment and a lack of accreditation.

The guidance now affirms this fact.

1.2 The word disclosure is often used in criminal proceedings to refer to the disclosure of unused material but experts in criminal proceedings have a number of different obligations as to disclosure.

1.3 Defence and prosecution experts are subject to the obligations contained in the Criminal Procedure Rules both in part 3 as to case management and part 19 as to expert evidence. Further guidance for all experts is contained in the 2015 Criminal Practice Direction that expands upon the Criminal Procedure Rules. These provisions oblige all experts to disclose certain information about themselves and their work.

1.4 Prosecution experts have further obligations as to the disclosure of unused material.

The slim chapter within the guidance which had been previously been titled “Disclosure obligations under the criminal law” has now been separated into two chapters titled “the disclosure obligations of all expert witnesses” (Chapter 3) and “the disclosure obligations of prosecution experts”(Chapter 4).

The guidance helpfully acknowledges that all expert witnesses are subject to a number of obligations to disclose information and material when preparing statements or reports for use in criminal proceedings and that it is the responsibility of those providing expert evidence to ensure they have an accurate understanding of the requirements of the criminal justice system and to meet those requirements. The guidance refers expert witnesses the Forensic Science Regulations here

The guidance reminds each expert to defer to the Criminal Procedure Rules (CrimPR) here and to keep firmly at the forefront of their mind the Criminal Practice Directions Division V, which make further provision as to expert evidence supplementing and expanding upon some of the provisions of the Criminal Procedure Rules. Full details are here

The guidance draws attention to the fact that the CPD V 19A.7 provides examples of information, namely adverse findings, failures or conflicts on the part of the expert, that should be disclosed by all experts under CrimPR 19.2(3)(d).

Chapter 4 specifically recognises that prosecution expert witnesses are subject to further obligations as to unused material and that although the material may not be used as evidence, it is important that for the purposes of disclosure this material is recorded, retained and where necessary revealed to the defence.

It confirms that three key obligations arising for the prosecution expert; retain, to record, and to reveal and that the understanding of these obligations is the key to adequately fulfilling disclosure obligations. The relevant steps are to:

4.5 provides a reminder that “the CPIA provides that the prosecution must disclose to the accused any prosecution material which might reasonably be considered capable of undermining the case for the prosecution against the accused or of assisting the case for the accused (the disclosure test)”.

Checklist as to how to prepare for instructing or challenging an expert witness;

  • Ensure the expert witness and you are familiar with Part 19 of the CrimPR and the relevant Practice Direction.
  • Reflect on the overriding principles of expert evidence as rehearsed by Gage LJ in R v Lorraine Harris [2005] EWCA Crim 1980 at [271] and the Court of Appeal’s recent commentary in R v Alex Julian Pabon [2018] EWCA Crim 420.
  • Make sure the expert has complied with the relevant formalities, as set out in the CrimPR.
  • Ensure the expert has signed a declaration of understanding in respect of their duties to the court (as per CPD V Evidence 19B)
  • Ensure you expert is candid in disclosing any potential skeletons in the closet – CPR amendment of 1 April 2019 requires disclosure of information that is likely to undermine the reliability or credibility of their expert’s evidence. The responsible expert would be well advised to make their own enquiries.
  • Request that the expert sets out their methodology, for instance the existence of independent statistical or empirical data which is capable of being independently reviewed. It is a matter of logic that if no independent review is possible, the evidence cannot be adequately tested and there will a viable argument against its admissibility.
  • As a minimum, confirm the expert has provided;
  1. A Self-Certificate
  2. A Declaration
  3. An index of unused material
  4. Read the Expert’s Revelation Process

The updated CPS guidance is helpful in that proformas of all the aforementioned are attached as appendices.

Categories: News | Newsflash