Written by: Shelley Gregory, PNLD Legal Adviser
Not reviewed after the date of publication - 25 January 2026
Parasomnia is a sleep disorder where an individual can experience an activity, behaviour or emotion when they are asleep, falling asleep or on waking up. This can include, for example, sleepwalking, sleep talking, crying, waking up confused, eating while asleep or initiating sexual activity. PNLD Legal Adviser, Shelley Gregory, will explore the parasomnia known as sexsomnia, and specifically the legal position when it is raised as a defence to rape.
Sexsomnia
Sexsomnia (also known as sleep sex) is a type of parasomnia whereby an individual engages in sexual activities and/or behaviour whilst they are asleep – this can include for example, touching themselves or others, masturbation and sexual intercourse with another person. A person exhibiting this behaviour may very well appear to be ‘awake’ to anyone witnessing them – they may have their eyes open or be making sexual noises - however, it would be quite normal for the person to have no recollection of their parasomnia.
Legislation
Rape is an offence of basic intent contrary to section 1(1) of the Sexual Offences Act 2003; subsections (1) and (2) provide:
“1(1) A person (A) commits an offence if –
(a) he intentionally penetrates the vagina, anus or mouth of another person (B) with his penis,
(b) B does not consent to the penetration, and
(c) A does not reasonably believe that B consents.
1(2) Whether a belief is reasonable is to be determined having regard to all the circumstances, including any steps A has taken to ascertain whether B consents.”
Section 74 of the Sexual Offences Act 2003 provides that, for the purpose of this offence, a person consents if they agree by choice and have the freedom and capacity to make that choice. Sections 75 and 76 of the Sexual Offences Act 2003 legislate for evidential and conclusive presumptions about consent respectively.
The points to prove for the offence of rape are:
- date and location
- intentionally without consent penetrated the anus / vagina / mouth of another person
- with penis
- not reasonably believing that they had consented
Defence of Automatism
Automatism refers to when a person has acted involuntarily - where their body has moved without conscious control. Automatism was defined in the case of Bratty v Attorney-General for Northern Ireland Respondent (1963) by Lord Denning:
“No act is punishable if it is done involuntarily: and an involuntary act in this context - some people nowadays prefer to speak of it as "automatism" - means an act which is done by the muscles without any control by the mind, such as a spasm, a reflex action or a convulsion; or an act done by a person who is not conscious of what he is doing, such as an act done whilst suffering from concussion or whilst sleep-walking.”
Automatism is a common law defence and is raised to establish that an accused could not form the mens rea for the offence. In relation to the offence of rape, the mens rea is the intentional penetration without consent or the absence of reasonable belief in consent – this is an objective test: it is not enough that the defendant genuinely believed in consent; the belief must also be reasonable in all the circumstances.
There are two types of automatism:
- Sane (non-insane) automatism – this occurs due to an external factor, for example, a blow to the head, sudden illness, or a reaction to medication.
- Insane automatism – this occurs due to internal factors, for example, sleepwalking, epilepsy, diabetes (hyperglycaemia), or mental illness.
In the case of R v Burgess (1991), Burgess, (B), and his neighbour, (V), spent the evening at V’s flat. V fell asleep and B hit her over the head and grabbed her round her neck. V cried out which brought B back to his senses. B then called an ambulance for V. At trial, B argued that he could not be guilty as he had not been conscious at the time of the offence. The trial judge ruled that where B had not been conscious at the time of the offence then it could amount to a defence of insanity within the M'Naghten Rules as opposed to non-insane automatism. B was found not guilty by reason of insanity and so ordered to be detained in a secure hospital. On appeal, it was held that it was for the judge to determine whether the evidence of automatism amounted to a form of sane or insane automatism. In this case, it was held that sleepwalking amounted to a disease of the mind within the M’Naghten Rules due to being an internal factor, and therefore, amounted to insane automatism rather than sane automatism.
In the case of R v T (1989), T was charged with robbery following her approaching a group of women at a vehicle, stabbing one of them in the stomach and demanding the handbag from another. T claimed that she could only recollect some of the events. T said that she had been raped 3 days prior to the event and her subsequent arrest. T was later examined on a number of occasions by a psychiatrist who diagnosed that after the rape she was suffering from Post Traumatic Stress Disorder and at the time of the offence she had entered a dissociative state, and the offences had been committed during a psychogenic fugue, and she was not acting with a conscious mind or will. It was held that where a defendant acted involuntarily, not aware of their actions and “as though in a dream”, the defence of automatism can be raised and should be left with the jury.
Therefore, it must be questioned whether the mens rea for the offence of rape can be established where the individual is in a dissociative state of automatism when they involuntarily engage in sexual intercourse. Consequently, a defence of automatism brought on by sexsomnia, can be raised as a viable defence to rape with the core legal argument in these cases being that the action (penetration) performed by the defendant during a genuine episode of sexsomnia is unintentional and involuntary on their part. It is for the judge to determine whether the jury should consider the defence of sane automatism, insane automatism or both.
If the cause is internal, as is generally accepted for sleep disorders like sexsomnia and sleepwalking, the courts are likely to treat it as insane automatism, with a potential verdict of "not guilty by reason of insanity" (within the M'Naghten Rules) being reached, rather than a full acquittal. However, both types of automatism defences are viable and, where the defence lay a proper foundation to demonstrate that the defendant was acting involuntarily, this should be left with a jury.
Where an automatism defence is raised, it is likely that expert evidence would be required, however, currently no experts can agree on diagnostic testing for sexsomnia, which causes concern regarding whether those claiming to have the condition are genuine. Nevertheless, there are both medical doctors and academics who assert that they can offer expert evidence in this area – and of course, a defendant can testify regarding the condition themselves. In 2011, at Burnley Crown Court, Alan Walker was convicted of assault by penetration, contrary to section 2 of the Sexual Offences Act 2003, following a failed sexsomnia defence. During his trial, both Walker and his wife, gave evidence and claimed that Walker was suffering from sexsomnia at the time of the offence and, therefore, he had not formed, or been capable of forming, the mens rea for the offence. The jury disbelieved the evidence of both Walker and his wife and convicted Walker (this conviction remained safe following an appeal on the ground of the good character direction - see R v Hunter and others (2015) for further details).
Concerns
Due to the lack of agreement on diagnostic testing, some critics assert that it is not possible to accurately diagnose sexsomnia or authenticate claims of those individuals who state they suffer from the disorder. This has led to a grave concern that the sexsomnia defence is open to abuse by people who falsely claim to be a sufferer of the disorder in an attempt to avoid criminal liability. The case of Joseph Short demonstrates the reality of the risk this poses.
Joseph Short was a soldier and in 2011, at Hull Crown Court, he successfully raised a sexsomnia defence and was acquitted of two counts of rape. In 2014, Joseph Short was charged with rape in Scotland, and this case was dismissed following the claim that he suffered from sexsomnia and the Crown received insights from a sexsomnia “specialist”. In 2016, at Birmingham Crown Court, Joseph Short faced charges of two counts of rape and one count of attempted rape and again raised a sexsomnia defence. This time the defence was unsuccessful, and he was convicted and sentenced to eleven years imprisonment, followed by a further four years on license. Joseph Short was a danger to the public but the success of the sexsomnia defence on numerous occasions left him free to commit further sexual offences and avoid criminal liability – this serial sex offender was finally held accountable for his actions when his sexsomnia defence failed.
The CPS appear to already be anticipating the availability of this defence for men in rape cases. In August 2025, the CPS reported a case in which Dean Final admitted he had physically, sexually and emotionally abused two former partners. One of the victims reported being forced into sexual activity and told the police in interview that Final’s eyes were closed while he raped her and that she thought he may have been asleep. The CPS recognised the potential availability of the sexsomnia defence in this case and intervened early to instruct an expert in sleep disorders. A successful application was made to the court to exclude any suggestion of sexsomnia to ensure the defence could not be relied upon to evade justice; ultimately, the defendant pleaded guilty.Automatism of the Victim
A defendant may raise automatism as part of the defence in relation to the victim’s actions, rather than being the whole defence itself in relation to them. The crux of this legal argument is that the defendant had a reasonable belief that the victim had consented to sexual intercourse as they believed them to be awake.
In 2017, Jade McCrossen-Nethercott reported to the police that she had been raped whilst she was asleep – she stated that she had woken up with a feeling that she had been penetrated, that she was half-naked and that she had found her broken necklace on the floor. Asking the male what he had done, she noted that he replied, “I thought you were awake”. The male was arrested and provided a no comment interview. The male was charged with the rape of Jade. Three years later, just days before the trial, the CPS discontinued the case because the defence alleged that Jade had experienced an episode of sexsomnia. This allegation was rebutted by Jade, but the CPS lawyer stated that they had received opinions from two sleep experts, (neither of which had met with Jade), who stated that it was possible for Jade to experience an isolated episode of sexsomnia, meaning that she could have appeared to the defendant to have been awake and consenting. Therefore, the defendant could not be guilty of rape because he had a reasonable belief in her consent. The defendant was acquitted.
In 2021, under the Victims’ Right to Review Scheme, Jade sought a review of the CPS decision to discontinue the case. An independent chief crown prosecutor reviewed the whole case again and concluded that the case should have gone to trial for the evidence to be put before the court. In 2022, Jade sued the CPS, and it was reported in 2024 that Jade was awarded £35,000 in a compensation settlement from the CPS. A spokesperson for the CPS said:
“A settlement has been reached with Ms McCrossen-Nethercott, to whom we have apologised unreservedly, and we continue to wish her the very best going forward…We remain positive about the progress being made and recognise there is still a long way to go to improve outcomes for victims, so more people can come forward and report with confidence.”
Conclusion
Sexsomnia can be a viable defence to a charge of rape, if raised as an automatism defence with supporting expert medical evidence. However, it can be seen as a controversial defence to raise as, without agreed diagnostic testing, ascertaining if someone is a genuine sufferer of the disorder is not currently possible. Therefore, the defence is open to abuse. Individuals who are accused of rape may attempt to misuse the defence and falsely assert they are a sufferer of the disorder and consequently evade criminal liability. Alternatively, they may raise the defence that the victim suffered an episode of sexsomnia and therefore they had reasonable belief that they had consented.However, automatism defences are renowned for being rare and difficult defences on which to rely but ultimately, from a legal perspective, where the defence are able to lay a proper foundation to demonstrate that the defendant could not form the necessary mens rea for the offence as he was acting involuntarily, the availability of the defence should be left with a jury who must determine, beyond all reasonable doubt, whether the defendant’s actions were voluntary or involuntary.
Only time will tell if medical advances in the area of sexsomnia will assist the legal world in relation to doubts about the credibility of sexsomnia being raised as a defence in rape cases.
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