Intimate sample prove/disprove intoxication

30 June 2021

Not reviewed after the date of publication


We were of the understanding intimate samples could not be taken to prove/disprove intoxication if it was not related to confirming or disproving their involvement or an offence.

However, the issue has been raised with a section 18 assault case. The rationale is that in order to prove someone's involvement in a section 18 offence it is not just necessary to prove the physical act but also that the relevant intent was formed. If that person was found to be impaired through drink/drugs and were unable to form the relevant intent then they would not be guilty of the offence.

When considering the taking of an intimate sample of blood to identify intoxication, could 'involvement' be interpreted as it is here, regarding intent?


An offence under section 18 of the Offences Against the Person Act 1861 requires specific intent and the type of intent will vary dependent upon which form of the offence is charged. The important thing to prove however, is the defendant's state of mind at the time.

In the case of R v McKay 2015 a conviction for wounding with intent was safe where an offender had run a defence of self-induced automatism and the judge had refused a defence application for an adjournment to obtain expert evidence about the effect that a combination of drugs and alcohol had had on the offender's intent. The defence of automatism was not available to an offender who had induced a state of automatism through their own fault.

Voluntary intoxication is generally considered to be no defence at all but might be relevant to whether the defendant formed a specific intention, if the offence in question required such (DPP v Majewski [1977] A.C. 443, [1976] 4 WLUK 71). Taking this view of voluntary intoxication, we would be of the opinion that to argue impaired intent is a matter for the defence rather than for the prosecution when considering evidence to charge and would ultimately be for a court/jury to decide. This is supported by the case of R. v Sheehan [1975] Crim. L.R. 339 in which it was held that:

'A jury should not be asked to decide whether a defendant through drunkenness was incapable of forming a specific intention; they should be warned that a drunken intention is nevertheless an intention, and, subject to that, having regard to all the evidence, they should be asked whether they are satisfied that the defendant, at the material time, in fact had the requisite intent.'

We do appreciate this may become a particular issue when murder or manslaughter is involved, and the person's intoxication may determine which offence the person is charged with. The establishment of the degree of intoxication and its effect on the ability of the suspect to form specific intent is a vital part of the investigation, and therefore an intimate sample is required to establish which offence they are involved in.

However, it is our opinion the taking of samples for the purpose of determining intoxication, not related to confirming or disproving their involvement in an offence, will not satisfy the provisions of section 62 of PACE and above, therefore no authority to take the samples can be given. Furthermore, in our view the issue when murder or manslaughter is involved could also be more easily interpreted as 'confirming or disproving' involvement in the offence; nonetheless, ultimately it would be for a court to decide.

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