Piloting Pre-Trial Witness Interviewing
Submitting InstitutionUniversity of Nottingham
Unit of AssessmentLaw
Summary Impact TypeLegal
Research Subject Area(s)
Studies In Human Society: Criminology
Law and Legal Studies: Law
Summary of the impact
This research informed the introduction and on-going implementation of a
major criminal policy innovation, namely, Pre-Trial Witness Interviewing
(PTWI) by Crown Prosecutors across England and Wales. It was conducted in
partnership with the Crown Prosecution Service (CPS), and provided
independent evaluation of PTWI as an integral component of the piloting
phase prior to national roll-out. The research formed part of the initial
PTWI training of selected Crown Prosecutors and, following roll-out,
continued to serve as a resource for frontline prosecutors, affecting case
progression, complainants' experiences and the outcomes of criminal cases
(prominently including serious sexual assaults and domestic violence).
Until very recently, pre-trial contact between prosecutors and witnesses
was forbidden in criminal proceedings in England and Wales. This
restriction (absent in many other common law jurisdictions) increasingly
came to be viewed as contrary to the interests of justice, as highlighted,
e.g., in public criticism of the CPS following the collapse of the first
Damilola Taylor murder trial. PTWI is a revolutionary development in
English criminal procedure, enabling prosecutors to interview key
witnesses at an early stage in the process for the purposes of improving
their decision-making in relation to charge selection, discontinuance and
case preparation for trial. PTWI may also ameliorate complainants'
experiences of criminal proceedings and assist witnesses to give their
best evidence in court.
In order to test and fine-tune the policy, CPS conducted a "live case"
Pilot of PTWI between January 2006 and April 2007. Extending previous
successful research collaborations in relation to special measures for
vulnerable and intimidated witnesses, , CPS engaged Professor
Paul Roberts as a consultant to devise and conduct an independent
socio-legal evaluation of PTWI in action during the Pilot phase. This
project was designed to ascertain (in conjunction with other monitoring
activities undertaken by CPS) whether, and to what extent, Pilot
interviews achieved their stated objectives, and to identify areas of best
practice and issues for further practical consideration , . A
qualitative socio-legal methodology was developed by Roberts, in
discussion with CPS Policy Directorate, to investigate the dynamics of
prosecutors' decision-making in relation to (i) case-selection; (ii)
interviewing strategy; (iii) interactions with other agencies (police;
counsel); and, crucially, (iv) the impact of PTWI interviewing on case
progression (decisions to charge, discontinue, secure further evidence, or
prosecute to trial).
CPS granted Roberts unparalleled access to the 20 or so Crown Prosecutors
selected and trained to conduct Pilot interviews, and also to CPS' own
monitoring data on the 93 Pilot cases in which PTWI was considered.
Sixteen in-depth, semi-structured qualitative research interviews were
conducted by Roberts or his then doctoral student and research assistant,
Candida Saunders, with Crown Prosecutors and Chief Crown
Prosecutors in the four CPS Pilot Areas. In addition, Roberts organised
and led three "training days" (run as large focus and discussion groups)
with these and other PTWI prosecutors in May 2006 and January 2007, which
also provided supplementary research data.
A comprehensive final report (c.110,000 words), detailing the research
findings and containing twenty-two specific recommendations for further
consideration, was presented to CPS Policy Directorate in April 2007. A
heavily abbreviated summary was published by CPS on its website in early
2008 , and this document formed part of the guidance provided to Crown
Prosecutors in PTWI's crucial formative years following national roll-out
in April 2008.
In brief, the research demonstrated empirically that PTWI could in
principle achieve its stated aims of improving prosecutorial
decision-making, promoting effective prosecutions and helping complainants
and other witnesses in the interests of justice. However, several
practical concerns— not just "teething-troubles"—were also identified
(including potential "witness coaching", non-cooperation, and
credibility/impeachment issues); and (i) prosecutor selection; (ii)
tape-recording; (iii) pre-trial disclosure; and (iv) the definition of
"new evidence" requiring supplementary witness statements were highlighted
as practical matters requiring further attention both pre-and
Paul Roberts was appointed to a lectureship in the University of
Nottingham School of Law in 1993, and has been Professor of Criminal
Jurisprudence since 2003.
Candida Saunders began her doctorate in the University of
Nottingham School of Law in 2005, and was appointed to a lectureship in
the School in 2008.
References to the research
2. Paul Roberts, Debbie Cooper and Sheelagh Judge, ;'Monitoring Success,
Accounting for Failure: The Outcome of Prosecutors' Applications for
Special Measures under the Youth Justice and Criminal Evidence Act 1999'
(2005) 9 International Journal of Evidence & Proof 269-290
4. Paul Roberts and Candida Saunders, `Introducing Pre-Trial Witness
Interviews — A Flexible New Fixture in the Crown Prosecutor's Toolkit'
 Criminal Law Review 831-853 [REF2 (Saunders)]
5. Paul Roberts and Candida Saunders, `Piloting PTWI — A Socio-Legal
Window on Prosecutors' Assessments of Evidence and Witness Credibility'
(2010) 30 Oxford Journal of Legal Studies 101-141 [REF2
6. Paul Roberts and Candida Saunders, `Pre-Trial Witness Interviews and
the "Justice Gap" — A Plea for Sophistication in Criminal Procedure
The preparation of outputs 3-6 was generously supported by AHRC Research
Leave grant AH/F005970/1 (£30,558, Sept 2007 — Jan 2008).
Details of the impact
The research was commissioned by CPS, specifically in order to develop
and implement evidence-based criminal justice policy, and to provide
operational guidance in its refinement. It represented the cementing of a
pioneering research partnership, affording exceptional research access—and
influence—of a kind that CPS has rarely granted to external researchers.
Although the primary research partner/stakeholder was CPS itself,
improvements in the quality of criminal prosecutions benefit all
concerned. Complainants should be treated more sensitively. Cases are
strengthened, improving outcomes; or discontinued more efficiently, saving
resources and sparing suspects from unnecessarily prolonged official
scrutiny or detention[i, ii, viii]. The ultimate beneficiary is society at
large, in terms of criminal proceedings better able to secure justice. In
the words of the Director of Public Prosecutions:
"Pre-trial witness interviews represent a fundamental change to our legal
system as prosecutors were not allowed to interview witnesses in any cases
in England and Wales before these CPS pilots began. I consider witness
interviews to be an essential tool to help prosecutors to make better
informed decisions about criminal cases so that the right person is
brought before the right court for the right offence"[iii].
Independent external research was regarded by CPS as a precondition of
national roll-out, and was therefore instrumental in promoting each of
these positive outcomes. As the CPS Policy Team Leader with responsibility
(at that time) for PTWI confirms: "[T]he evaluation process, incorporating
your socio-legal study, was of considerable assistance to the prosecutors
in the pilot areas and assisted me in informing the content of guidance
and training that we provided and continue to provide. I think it also
fair to say that the contents and conclusions of your summary report
contributed to the decision to roll it out in the first place.... [Y]our
research was useful to CPS in developing this significant initiative in
The published research findings and analysis, in conjunction with
informal advice to CPS, have continued to contribute to the further
refinement and implementation of PTWI on a rolling basis:
(1) Following completion of the PTWI Pilot and its evaluation
(centrally featuring Roberts and Saunders' socio-legal research), the
decision to implement PTWI nationally was announced in 2007
(Statement of Baroness Scotland, Attorney-General, HL Deb 27 Nov 2007, vol
696 cols 142-143WS; Statement of Vera Baird MP, Solicitor-General, HC Deb
27 Nov 2007, vol 468 col 24WS). PTWI was successfully rolled-out to all 42
CPS Areas in England and Wales in April 2008. A CPS press release stated:
"The initiative was trialled in four CPS areas from January to December
2006, on the basis of which a decision was made to roll out the initiative
throughout England and Wales"[iii]. The CPS Annual Report for
"Between January 2006 and January 2007, the pre-trial witness interview
(PTWI) scheme was successfully piloted in four CPS Areas.... Following the
pilot, the four CPS Areas have continued to undertake PTWIs — by January
2008 over 90 interviews had been conducted, predominantly in serious
cases. An external evaluation concluded that the scheme improved
prosecutorial decision-making by strengthening cases which went to trial
and rejecting potentially weak cases at an early stage. National
implementation was achieved on time in April 2008 and around 180
prosecutors have been trained to undertake PTWIs".[iv, emphasis supplied]
Many informed observers were initially sceptical or hostile to the
introduction of PTWI[v]. Crucially, the Pilot Evaluation research drew
attention to risks and potential shortcoming which would require on-going
monitoring and effective management to ensure the success of national
Building on the influence of the research in helping to pave the way for
PTWI's national roll-out, the principal on-going impacts of the research
post roll-out (April 2008 onwards) are attributable to:
(2) The experience gained by Pilot prosecutors who participated in the
"training days", and subsequently became PTWI "champions", extolling
the benefits of PTWI and passing on tips to their front-line colleagues.
The "training days", devised and run by Roberts, were organised around
presentations, by Roberts, of provisional results of the socio-legal
study, which were debated at length by prosecutors (and the research
findings augmented accordingly). Pilot prosecutors said that these
sessions were invaluable opportunities to pool experiences, and that there
was no substitute for face-to-face instruction and discussion, e.g. one
prosecutor emphasised the indispensability of "[a]wareness training...
informing lawyers in a lecture or seminar scenario. Whilst lawyers have
memos and written guidance, they are less likely to read and digest
information, as they have other pressing concerns. A course, however,
ensures they are made aware". The study's "training days"/focus groups are
regarded by CPS as having made an on-going, long term contribution to the
development, practical implementation and refinement of PTWI: "[A] useful,
possibly overlooked, aspect of your evaluation report was that you brought
together a lot of scenarios and views in one document, which made it
easier to pick through and discuss potential pitfalls in the pilot
evaluation meetings and later in the training sessions" [vi].
(3) On-going influence on CPS operational policy guidance. CPS
internal documentation and operational guidance on conducting pre-trial
interviews was systematically revised in the light of the Pilot: see http://www.cps.gov.uk/legal/p_to_r/pre_-trial_witness_interviews/.
In particular, the summary research report written by Roberts and Saunders
[i] was hosted on the CPS website from January 2008 to mid-2013, and
during this time formed part of the operational resources provided to
front-line Crown Prosecutors in considering and conducting pre-trial
PTWI continues to figure in developments of CPS operational policy, e.g.
in revised guidance for prosecutors in relation to rape and sexual
offences, which now states: "The use of pre-trial witness interviews
(PTWI) is considered an effective tool in rape cases. This will
particularly apply in cases where the decision to prosecute is
'borderline'. In June 2009... the DPP instructed that prosecutors should,
as part of their decision-making in every rape case, consider whether or
not a PTWI is appropriate and provide reasons for their decision... This
instruction remains in force and should be followed in every case"[vii].
This echoes our research finding of "several striking illustrations in the
Pilot cases in which convictions were achieved that probably could not
have been secured without the benefit of a pre-trial witness interview"
(4) International policy transfer: Dissemination of research
findings is still on-going, especially in terms of international
impact[ix]. There has been interest from senior prosecutors and
policy-makers overseas, e.g. Hong Kong[x], in examining English
experiences of PTWI.
Sources to corroborate the impact
i. Paul Roberts and Candida Saunders, Interviewing Prosecution
Witnesses: A Socio-Legal Evaluation of the Pre-Trial Witness Interview
Pilot (CPS, 2008), 38pp, was hosted 2008-13 at
and summarised in Paul Roberts and Candida Saunders, `Introducing
Pre-Trial Witness Interviews — A Flexible New Fixture in the Crown
Prosecutor's Toolkit'  Criminal Law Review 831-853.
ii. Clare Dyer, `Criminal Justice Revolution to Secure More Convictions —
Plan for prosecutors to interview witnesses before trial will end ancient
rule' The Guardian, 11 November 2005 (front-page headline).
iii. "CPS announces the roll out of two key justice initiatives", CPS
Press Release 1 April 2008,
(originally, with hypertext link to i).
iv. Crown Prosecution Service Annual Report 2007-2008. HC 619
v. Polly Botsford, `Early Warnings — Pre-trial interviews for Barristers
are not far off but the reforms bring potential hazards alongside welcome
benefits', Law Society Gazette, 28 March 2008.
Liberty's Response to the CPS Consultation on Pre-Trial Witness Interviews
by Prosecutors. (Liberty, July 2003).
Criminal Bar Association Response to `Pre-Trial Witness Interviews by
Prosecutors, A Consultation Paper'. (CBA, July 2003).
vi. Mr Dan Jones, Specialist Prosecutor (Special Crime and Counter
Terrorism Division), Crown Prosecution Service (e.g. letter to PR dated 17
vii. CPS Legal Guidance, Rape and Sexual Offences: Chapter 7: Pre-Trial
viii. Paul Roberts and Candida Saunders, `Pre-Trial Witness Interviews
and the "Justice Gap" — A Plea for Sophistication in Criminal Procedure
ix. Paul Roberts, "Prosecutors Interviewing Witnesses: A Question of
Integrity?", paper to mixed academic/practitioner criminal justice
seminars in Hong Kong (Dec 2012) and Sydney (April 2013):
x. Legislative Council Panel on Administration of Justice and Legal
Services (2008), Information Paper on Pre-trial Interviewing of
Witnesses by Prosecutors, LC Paper No. CB(2)2327/07-08(05).
Submission of the Hong Kong Bar Association — Pre-Trial Witness
Interview By Prosecutors (HKBA, Oct 2009)