These and other questions could be approached from a range of angles. It is clear, however, that an overriding concern is whether criminal justice and mental health systems deal fairly and equitably with mentally disordered offenders. The Law Commission – whose statutory function is to ensure that the law is as fair, modern and simple as possible – has focused on two separate but linked aspects of the concern. The first relates to an accused who was mentally disordered at the time of the offence and is governed by the defences of insanity and automatism. The second relates to an accused who is mentally disordered at the time of criminal proceedings and asks whether he or she is fit to plead and stand trial. Both legal tests have their roots in nineteenth century cases (M’Naghten, 1843 and Pritchard, 1836 respectively), when the science of psychiatry was in its infancy. The criteria for both tests are widely regarded as outmoded and ripe for reform.

The linked issues of unfitness to plead and insanity

The Law Commission started work on these linked issues by publishing a consultation paper in 2010 containing provisional proposals for reform of unfitness to plead. We are in the process of refining these proposals in light of responses from consultees and plan to publish a final report in 2014. Meanwhile, in 2012, the Commission published a scoping paper to gather more evidence about the practical operation of the insanity and automatism defences. While legal and medical practitioners agreed with our assessment that there were many academic criticisms to be made of the defence, they noted that these flaws are mitigated by practitioners working around the problems. Many consultees told us that the reform that is more pressing in practice is to the law and procedures governing unfitness to plead. In light of this and because we anticipate greater governmental support for reform where there is an acknowledged practical need, we have decided to prioritise our work on unfitness to plead.

At the same time, we are anxious to keep alive the debate on reform of insanity and automatism. We have therefore published a discussion paper (DP) with our provisional thinking on reform, and intend to return to the project with a consultation in due course. This prioritisation not only reflects the practical priorities confirmed to us in the scoping paper; it is also the most logical approach. It is important to get the unfitness test right first because of the “filtering” function it performs. One of the key flaws of the present test is that it sets the threshold for unfitness too high, creating the risk of unfairly exposing people to a criminal trial who are unable to participate effectively in the proceedings against them. If the unfitness test were reformed, fewer people with serious mental disorder would face trial, and the (already small) number of people seeking to rely on a reformed insanity defence would decrease further.

The scope of the discussion paper on insanity and automatism

The question at the heart of the DP is whether the law employs the right test to distinguish between those who should be held criminally responsible and those who, by reason of their condition, should not. The scope of the paper is limited by the fact that the insanity and automatism defences are only part of the larger picture: it lies outside our remit to engage in a comprehensive review of the position of mentally disordered offenders in the criminal justice system.

The limbs of the M’Naghten test, as interpreted by the courts, have received much criticism for drawing illogical distinctions (for instance between impaired powers of reasoning and impaired powers of control; or between “internal” and “external” factors causing a loss of control) and for being unduly restrictive (for instance excluding someone from the ambit of the defence where they have knowledge of the physical but not moral aspects of the act alleged; or where they know the act is legally wrong but do not appreciate it is morally wrong). In addition, practitioners who responded to our scoping paper confirmed our view that the label “insanity” is stigmatising and inaccurate, frequently making it difficult to raise the possibility of relying on the defence with clients.

A new defence of “not criminally responsible by reason of recognised medical condition”

The abolition challenge
Our starting point in the DP is to consider whether there is a need for an “insanity” defence at all. One alternative would be simply to ask whether the accused’s mental disorder negates the mens rea required for the offence in question; where it does, the accused should be acquitted outright with no disposal. This “abolition proposal” may have the virtue of simplicity, but glosses over important questions about the theoretical foundations of criminal responsibility. We consider that the crux of the insanity defence is that it is unjust to hold a person criminally responsible when, through no fault of their own, they could not have avoided committing the alleged offence. Where mental disorder causes a person to lack criminal responsibility, it would be inaccurate to describe that person as lacking mens rea. The question of criminal responsibility ought logically to precede consideration of whether the elements of an offence have been satisfied.

We conclude, therefore, that there should be a specific defence founded on the absence of criminal responsibility, where this is caused by a recognised medical condition. We see no principled reason, however, to limit the defence to mental disorders, provided always that the physical condition in question caused a total lack of capacity.

A total loss of a relevant capacity
The key requirement of our proposed defence is that the accused must have totally lacked the capacity to conform to the relevant law. The new special verdict would be available where the accused wholly lacked the capacity:

  • rationally to form a judgment about the relevant conduct or circumstances;
  • to understand the wrongfulness of what he or she is charged with having done; or
  • to control his or her physical acts in relation to the relevant conduct or circumstances

as a result of a qualifying recognised medical condition.

These specified capacities are those we consider necessary in order for a person to bear criminal responsibility. “Capacity” here is issue and time specific, as with the civil law test for capacity under section 3 of the Mental Capacity Act 2005: the question is whether the accused lacked a specified capacity in relation to the charge he or she is facing.

Recognised medical condition
The total lack of capacity would have to be caused by a recognised medical condition. Determining what constitutes a “recognised medical condition” is a question of law. Not all medical conditions, however, will qualify. For instance, where an accused’s condition consists of a personality disorder characterised solely or principally by abnormally aggressive or seriously irresponsible behaviour (and so the evidence for the condition is simply evidence of what might broadly be termed criminal behaviour), the defence would not be made out. Acute intoxication (where voluntary) would also not qualify. Our reformed defence would therefore offer an integrated solution which fits with established principles of prior fault and intoxication.

The link between insanity and automatism
Redefining the defence to include physical disorders causing a total loss of capacity (for instance diabetes leading to a hypoglycaemic coma) would mean that some people who currently receive an outright acquittal on grounds of “sane” automatism would instead receive the new special verdict of “not guilty by reason of recognised medical condition”. This produces more satisfactory outcomes because the court, once it has delivered the special verdict, would have the power to attach a disposal based on health grounds for public protection. This option is currently not available in a sane automatism case, even where the accused has caused harm by reason of a physical condition and may be at risk of doing so in future because the harmful behaviour may recur.

Readjusting the boundaries between the defences of insanity and automatism would also bring other benefits. The defence of automatism is currently available where the accused totally lacked control of his or her body at the time of the offence and was not at fault for this loss of control. In its present form, the defence is premised on an unstable distinction between “internal” and “external” factors which translate into pleas of “insane” and “sane” automatism respectively. Our proposal to redefine the insanity defence to include physical conditions causing a total loss of capacity would avoid the need to rely on this unsatisfactory distinction. The new defence of automatism would therefore only apply where the accused was unable to control his or her actions for reasons other than a recognised medical condition.

Procedural questions
We consider a number of procedural issues in the DP. We propose, for example, that the reformed defences should be available in the same form in the magistrates’ courts as well as in the Crown Court. We also suggest that magistrates should have the power to make a supervision order and a non-penal “youth supervision order” (a new disposal we recommend for under 18s) in the event of a special verdict.

Burden of proof
The current law places the legal burden of proving insanity on the accused. This is best explained as a historical accident and fails to give effect to the presumption of innocence in article 6(2) ECHR. We recommend that the legal burden of proving sanity should rest on the Crown, but that the accused should bear an elevated evidential burden and be required to adduce evidence of the new defence from two experts – this being necessary to prevent the risk of “trial by expert”.

Striking the right balance

The overarching aim of our proposals is to ensure fair treatment of mentally disordered offenders, while balancing this against the need for protection of the public. Through the publication of the DP, we hope to be able stimulate public debate about this difficult and important issue. The DP, as well as a summary, is available at:

Daniella Waddoup, research assistant at the Law Commission