Ask an expert: Could sleepwalking lead to jail?

Mark Thomas, a senior lecturer at Nottingham Law School, sheds some light on the use of sleepwalking as a defence in criminal cases. 

  • Last updated Jan 13, 2020 12:36:29 PM
  • Mark Thomas, Senior lecturer at Nottingham Law School

It doesn’t seem like a day goes by without the nation’s sleeping habits being discussed in the media. Up to a third of British people report problems having a good night’s sleep and our busy lifestyles, coupled with more technology such as smartphones, smartwatches and laptops by the bedside, have been blamed for giving us restless nights.

Beyond restless nights or bouts of insomnia, it’s not uncommon for people to suffer from sleepwalking or night terrors. According to the NHS, there’s no known cause for sleepwalking, but it does tend to run in families. Triggers of sleepwalking include not getting enough sleep, stress and anxiety, drinking too much alcohol and taking recreational drugs, amongst other factors; such triggers can also make sleepwalking worse. These sleepwalking episodes can be unsettling for the sleepwalker and those around them. In worst-case scenarios, sleepwalking can cause extreme behaviour beyond the sleepwalker’s control, such as leaving the house or even getting into a car. 

Can you commit a crime whilst sleepwalking?

Whilst it’s not common, there are examples of individuals committing crimes whilst sleepwalking. Recently, 21-year old Dale Kelly was cleared of sexually assaulting a woman after the jury found he could not be held responsible for his actions as he was suffering from parasomnia at the time—a sleep disorder which involves abnormal movements and behaviours during sleep. 

Kelly, who had been on a night out, got into bed with friends and touched the woman intimately—an act which he couldn’t remember.  

Can you defend a crime committed whilst sleepwalking?

Few cases come before the courts which use sleepwalking as a defence. This is partly because medical evidence is required to support this claim (which could be contested by the prosecution) or if drugs or alcohol had been used, it could be argued this brought on the sleepwalking. 

In the case of Kelly, he was found not guilty by reason of insanity. Again, this is quite unusual and not without its own issues. Following an acquittal by reason of insanity, a defendant is not entitled to just walk free. Instead, the trial judge must consider whether to detain the individual by way of a Hospital Order, issue a Supervision Order or release him. The case of Dale Kelly is currently being considered by the judge, who said, "At the moment I'm leaning towards a hospital order but I will wait to hear what the experts say." 

Is it “insane” to sleepwalk?

A person who happens to commit an offence whilst sleepwalking can be considered to be legally “insane” despite little basis in medicine or law to justify the use of such a term. Indeed, the authors of Smith, Hogan and Ormerod’s Criminal Law suggest that to use the term “insanity” is “profoundly misleading”. 

Insanity as a defence came about as a result of a 1991 Court of Appeal case, R v Burgess [1991] 2 QB 92, which concluded that sleepwalking should be regarded as a defect of reason, caused by a disease of the mind (i.e. insanity) as opposed to being caused by an external factor (i.e. automatism).

However, there has not been legal consistency, as following on from this 1991 case a number of Crown Court cases have involved acquittals on the basis of automatism, as opposed to insanity. 

These included R v Bilton (2005), which concerned a charge of rape, and R v Davies (2006) which concerned a sexual assault. In addition, cases have been discontinued by the Crown Prosecution Service on the basis that it would not be in the public interest to hospitalise an individual who commits an offence whilst sleepwalking—this was seen in the case of Brian Thomas who murdered his wife in 2009 whilst on a caravan holiday after dreaming they were being attacked by intruders. In this instance, the CPS ruled that "no useful purpose would be served by Mr Thomas being detained".

Could the law change?

In the past, there have been attempts to change the law on this point. In October 2008, MP Harry Cohen introduced a Private Member’s Bill entitled the Rape (Defences) Bill. The Bill was introduced to amend the Sexual Offences Act 2003 to prohibit the defence of sleepwalking or other automatism from being claimed in cases of rape following the media coverage of a number of cases where defendants successfully raised a defence of sleepwalking to charges involving sexual offences. The Bill stalled after its first reading. 

Sleepwalking case studies

Compiled by Becky Kells 


Case study 1 - Albert Tirrell 

The first successful use of sleepwalking as a defence in American legal history took place in 1846, in the trial of Albert Tirrell. Tirrell had left his wife the previous year to be with a prostitute, Maria Bickford. In spite of an apparent close bond, Tirrell reportedly resented Bickford for continuing her sex work in spite of their relationship. She was found murdered in October 1845. It is alleged that Tirrell visited her room after a customer had left it and slit her throat with a razor, almost decapitating her. He was also reported to set three fires in the brothel where Bickford worked. Tirrell’s lawyer Rufus Chote successfully argued that Tirrell could have been suffering from a nightmare or trance when he killed Bickford and referred to popular descriptions of violent sleepwalking incidents to convince the jury. It worked—Tirrell was found not guilty on March 30 1846. 


Case study 2 - Jules Lowe 

On October 30 2003, a 32-year-old man from Manchester killed his 83-year-old father by punching, stamping and kicking him, eventually leaving him in the driveway of their shared home. Jules Lowe reportedly had a close relationship with his father, and they had been drinking together in the house prior to the attack. Lowe did not deny the attack but said that he was not aware of his actions during it, as he was in a state of automatism (or sleepwalking). To verify this, Lowe underwent a number of overnight sleep studies prior to his trial, carried out by Dr Irshaad Ebraim of the London Sleep Centre. On March 18 2005, Lowe was cleared of murdering his father, with his sleepwalking defence accepted by a jury, He was, however, found not guilty of murder on the grounds of insanity. He was detained in a mental hospital as a result of the attack. 


Case study 3 - Zack Thompson 

The sleepwalking defence has also been initially adopted by defendants and later been debunked. This is true in the case of Zack Thompson, who raped a then-17-year-old girl in a Portuguese holiday resort in 2009. Thompson’s case was just the second sleepwalking case in the UK to be successfully challenged. Thompson was under the influence of alcohol when the rape took place, and could not remember anything of the evening beyond drinking seven or eight pints. Thompson did report to his local police station as soon as he returned to the UK but said he was sleepwalking when he committed the act and had no memory of it. Sleep disorder expert Professor Mark Pressman found that Thompson behaved in a way that is inconsistent with the normal behaviours of sleepwalkers. After withdrawing his sleepwalking defence, Thompson unsuccessfully tried to claim he was insane at the time of the rape, eventually pleading guilty to the crime at Nottingham Crown Court on March 1 2012, over two years after committing the crime. 


Case study 4 - Joann Kiger 

In 1943 in rural Kentucky, father and son Carl and Jerry Kiger were fatally shot, while Carl’s wife—Jennie—was wounded by a bullet to the leg. Jennie and her 15-year-old daughter Joann were charged with murder in the absence of any evidence of a break-in. It emerged that Joann had suffered from night terrors, and in the trial, it was proposed that Joann had dreamt of a disturbance in the family home. Her actions—to arm herself with two loaded revolvers and fatally shoot her family members—were put down to sleepwalking. She was acquitted on the grounds of insanity and the charges against her and her mother was dropped. After spending a year in a mental institution, Kieger changed her name and went on to live a full life. 


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