Sex by deception is a crime

Over the weekend, I posted this thread on X about a horrific set of crimes involving a brutal assault following at least two sexual offences. I was clear that my purpose in writing that thread was to inform people about the applicable law, including a knotty area of law relating to sex by deception. Unsurprisingly, several bad faith actors have now accused me of attempting to minimise the assault by mentioning the sexual offences that likely occurred, if the reported facts are accurate. Others have argued that transgender people cannot be liable for the crime of sexual assault by deception or that there is no case law on this specific question so lawyers cannot and should not extrapolate general legal principles.

In this post, I will explain the law on sexual assault by deception and explore some of the cases that have been decided which establish that deceiving someone as to your biological sex can vitiate consent. Several of these cases involve defendants who have a trans identity or who were experiencing gender dysphoria at the time of the offence. This does not grand an immunity to liability.

Sexual assault by deception

For crimes such as sexual assault, assault by penetration, and rape, lack of consent is a central element of the offence. Section 74 of the Sexual Offences Act 2003 states that to consent, one must agree by choice and have the freedom and capacity to make that choice. A common misconception about sexual offences is that lack of consent is all that is needed to establish liability for sexual contact, but this is not true. There must also not be a reasonable belief in consent. If someone does not consent to sexual activity but it would be reasonable for the other party to conclude that there was consent, then the crime has not been committed. However, cases involving deception tend to establish this relatively easily because the nature of the deception tends to lend itself to an understanding that, without the deception, consent would not be forthcoming.

The circumstances where an operative deception can vitiate consent are narrow. Current case law sets out a test which looks to whether the deception is sufficiently proximate to the nature and purpose of the sexual act itself rather than extraneous or background circumstances. For example in Assange v Swedish Prosecution Authority, it was held that lying about wearing a condom during sex constituted a deception that was sufficiently proximate to the nature of the act of penile penetration such that it vitiated consent. Similarly, in R (F) v DPP, a lie about intending to withdraw before ejaculation was sufficiently proximate to the nature and purpose of the act to vitiate consent.

However, a deception as to something which is extraneous to the nature or purpose of the sexual act will not vitiate consent, even if one party would not have consented had they been aware of the deception. For example, in R (Monica) v DPP, the High Court concluded that a deception as to certain features of identity did not vitiate consent because it was not sufficiently proximate to the nature or purpose of the sexual acts in question. In Monica the deception arose by virtue of an undercover police officer infiltrating an activist group and forming a sexual relationship with one of its members. While the complainant would not have consented to sexual activity had she known that the defendant was an undercover police officer, this deception was not sufficiently proximate to vitiate consent.

Similarly, in R v Lawrence, the Court of Appeal concluded that a deception as to fertility was not sufficiently proximate to vitiate consent. In Lawrence, the appellant had lied about having undergone a vasectomy and this deception had induced the complainant into having unprotected sex. Notwithstanding the fact that consent would not have been forthcoming had the complainant known that Lawrence was fertile, the Court concluded that the existing statutory framework only allows for the vitiation of consent by deception where the deception is more closely related to the nature or purpose of the acts themselves. Deception as to the background circumstances was not sufficiently proximate.

Deception as to sex