REF: 2021

Impact case study

Improving justice by establishing a test of "fitness to plead" in criminal courts


Professor Peay’s research, together with Dr Nigel Blackwood (Institute of Psychiatry) and Dr Michael Watts (UCL), addresses the core issue of fairness in the criminal justice system, by providing a legal mechanism for ensuring that those who cannot be tried fairly are not exposed to conviction and punishment.

Professor Jill Peay

Research by

Professor Jill Peay

LSE Law School

LSE research has participated in devising a tool to help prevent individuals standing trial when they cannot be tried fairly.  

What was the problem? 

The prison population for England and Wales has consistently exceeded 80,000 in recent years. Levels of diagnosable mental health disorder remain prominent amongst prisoners.   

This can only cast doubt on the fairness of some of their convictions, while also questioning the continuing applicability of current procedures for assessing a defendant’s fitness to plead. These are based on the leading 19th-century case, R v Pritchard (1836). This, and subsequent case law, considers a defendant’s ability to comprehend trial proceedings so as to make a proper defence and is now determined in each case by a judge, based on the advice from clinical assessments.  

Government, legal practitioners, civil liberties advocates, and academics have all expressed concern about whether fitness to plead assessments are appropriate for modern trials or whether they set the threshold too high.  

The Law Commission has also noted that existing unfitness criteria are potentially incompatible with the European Convention on Human Rights (ECHR), and its requirements under the right to a fair trial that defendants are able to participate effectively in the trial process. A fair and efficient trial process needs to uphold the rights of vulnerable defendants whilst also protecting the interests of complainants and the public from harm.  

What did we do? 

In response to these concerns, the Law Commission initiated a consultation programme to consider reform. Alongside this, in 2009, Professor Jill Peay, Dr Nigel Blackwood (Institute of Psychiatry), and Dr Michael Watts (UCL), established a cross-disciplinary project, supported by the Law Commission and a Nuffield Trust grant, to develop a psychometrically sound method of assessing an accused person’s ability to plead to an indictment.  

Professor Peay assisted in providing the expertise in mental health and criminal law necessary to design and test a legally appropriate instrument for determining the core cognitive abilities an accused person would need to participate meaningfully in the trial process.  

In consultation with legal and clinical practitioners, an outside professional script was developed for a typical short court case and a testing instrument was devised to probe an accused person’s understanding of the trial and the court process. The script was cross-checked for authenticity with senior judges and filmed with professional actors. The point of view adopted was that of the defendant. The resulting film was then shown to a demographically representative group of 200 participants and to groups representing people who might experience difficulties with trial proceedings, such as those with learning disabilities and mental health problems. Participants were required to put themselves in the position of the defendant. As the film progressed, they were asked a series of questions set out in the accompanying legally informed instrument. As a result of this testing phase, amendments were made. A second round of testing was held with a further 160 subjects, leading to a validated test of fitness to plead.  

The methodological challenges the team addressed included taking into account participants’ previous experiences of the criminal justice system, making the instrument gender neutral, and considering the role of the instrument among participants faking cognitive impairment (legal malingering).  

The team’s research addresses the core issue of fairness in the criminal justice system by providing a legal mechanism for ensuring that those who cannot be tried fairly are not exposed to conviction and punishment. Peay, Blackwood, Watts, and their collaborators have developed a psychometrically sound method of assessing an accused person’s ability to plead to an indictment, to understand court proceedings, to follow trial evidence, and to participate effectively in their trial.  

What happened? 

The novel instrument has informed legal debate on how best to establish an accused person’s fitness to plead. The research has also contributed to the Law Commission’s own work in this area. In 2014, the Commission published “Unfitness to Plead: An Issues Paper” to solicit the views of those with experience of the criminal justice system, ahead of making its final recommendations to government. With respect to developing a defined psychiatric test to assess a defendant's decision-making capacity, the paper explicitly endorsed this research: “No standardised model was put forward in the [Consultation Paper], but we endorsed research being conducted into such a formulation.”  

Following consultation, the Law Commission published its revised proposals in a final report in 2016, together with a Draft Bill, which recognised Professor Peay and her collaborators’ contributions. A fitness to plead psychiatric test based on the project’s findings was one of the key planks in these proposals, noting its benefits in terms of increased time and cost efficiencies:  

An initial assessment might obviate the need, in some cases, for a full report to be prepared, with all the attendant costs and delays, or at least identify more clearly the appropriate expert to approach. We hope that the work currently being conducted on screening tools might also assist in making screening robust and effective.

In a government response to the Law Commission’s proposals, Mike Penning MP, former Minister of State at the Ministry of Justice, welcomed the “balanced and thorough consideration of how to ensure that defendants who lack the capacity to participate in trial are dealt with appropriately in the criminal courts”. Clinicians have recommended field trials of the Law Commission’s proposals, augmented by the use of test instruments. The instrument was subsequently put into “real-world” testing in the Magistrates’ Court by another of its co-authors, Dr Penny Brown at the Institute of Psychiatry.  

Assessment of the wider impacts of this instrument remains under consideration. However, in their latest white paper on mental health law reform, the government have indicated an intention to consider the Law Commission’s reforms. These would facilitate a fairer and more efficient trial process that balances the rights of vulnerable defendants, whilst protecting the interests of complainants and the public from harm. This can only enhance confidence in the criminal justice system.