Why Sex Matters is taking the CPS to court over its guidance on deception and consent

This week, the High Court will hear Sex Matters’ challenge to the Crown Prosecution Service (CPS) guidance on deception and consent in sexual offence cases.

At the heart of the case is a straightforward question: can the CPS lawfully tell prosecutors that a person’s “gender identity” may be legally relevant when deciding whether deception invalidates consent to sex? Sex Matters says the answer is No.

The case will be heard on 8th and 9th July 2026 at the Royal Courts of Justice. We are represented by Sarah Vine KC and Chris Knight KC. 

How we got here

This hearing is the culmination of more than four years of engagement with the CPS about whether its guidance is an accurate statement of the criminal law. 

In May 2021 the CPS published guidance called “Deception as to Gender” as a section in its Rape and Sexual Offences Prosecution Guidance (under Chapter 10: consent). It sought to explain how prosecutors should apply section 74 of the Sexual Offences Act 2003 in cases where someone alleges that their consent to sexual activity was obtained through deception about a partner’s sex.

The CPS had been a member of the Stonewall Champions scheme and it updated the guidance following a “preconsultation with interested groups” that included the Government Equalities Office, LGBT charity Galop, Mermaids, Gendered Intelligence, LGBT Consortium, LGBT Foundation, Scottish Trans Alliance and Stonewall, along with organisations concerned with violence against women. 

The updated draft guidance it published in 2022 confused biological sex and gender identity and presented them as parallel concepts. The section entitled “Evidential considerations” advised that a suspect’s trans identity, if genuine, should be treated as evidence that a deception as to sex was not deliberate, and that trans suspects had no duty to disclose “gender history” (by which it meant their sex). 

Sex Matters and the Gay Men’s Network both raised concerns, arguing that the guidance did not accurately reflect the law. 

In December 2024, the CPS published a revised version, which was now called “Deception as to Sex”. Although some wording had changed, the central problem remained: prosecutors were repeatedly directed to consider “sex and/or gender identity” as though the two concepts were legally interchangeable. The guidance suggested that the suspect’s rights to privacy protected by Article 8 ECHR, the Equality Act 2010 or the Gender Recognition Act 2004 might trump the right of the complainant to understand what she or he is consenting to in an act of a sexual nature.

In February 2025, Sex Matters sent a formal pre-action letter explaining why we believed this guidance was unlawful.

The CPS asked for additional time to respond. Over the following months, we exchanged extensive correspondence. It accepted that some amendments were needed and proposed a number of changes to the guidance. But it refused to abandon its core position that “gender identity” could be relevant to the legal test for consent.

Following the Supreme Court’s judgment the CPS amended the guidance again, inserting the word “biological” before “sex” at numerous points. This didn’t help; while sex is by definition biological, adding that word in this way tends to suggest there is another relevant kind of sex that isn’t biological (or that “biological sex” and “gender identity” are two parallel characteristics).  The most recent version of the guidance was updated in June 2026.

What does the law say?

The Sexual Offences Act 2003 sets out the offences requiring the prosecution to prove absence of consent. They are rape, assault by penetration, sexual assault and causing a person to engage in sexual activity. In relation to these offences, a person (A) is guilty of an offence if she or he acts intentionally, and (B) does not consent to the act, and (A) does not reasonably believe that B consents.

English law recognises that some forms of deception can invalidate consent to sexual activity. But not every lie between sexual partners is a criminal offence.

The Court of Appeal has made clear that the deception must be “so closely connected to the performance of the sexual act” that it is capable of negating consent. That is the legal test established in R v Lawrence [2020]. Cases involving deception about fertility, HIV status or other wider circumstances have generally failed that test. Cases involving deception about the nature of the sexual act itself, such as secretly removing a condom or pretending a sexual act is a medical procedure, may satisfy it.

The key precedent on deception related to sex is R v McNally, in which the Court of Appeal held that deception about whether a person is male or female could invalidate consent. (Sarah Vine KC discussed the legal concepts with Michael Foran on his podcast in 2024).

Sex Matters argues that the CPS guidance is unlawful as it treats gender identity as though it were equivalent to sex. We say that a person’s gender identity (whether they identify as a transwoman, transman, masc, femme, non-binary, gender fluid or anything else) is not part of the performance of the sexual act and therefore cannot satisfy the Lawrence test. As the Supreme Court recognised in For Women Scotland: 

“People are not sexually oriented towards those in possession of a certificate.”

The CPS disagrees and says that the matter should be left to a jury in an appropriate case.

The hearing on 8th and 9th July 2026 will therefore focus on a fundamental point of principle: is gender identity legally relevant to deception under section 74 of the Sexual Offences Act 2003?

Why the guidance matters

Crown Prosecutors are expected to follow CPS guidance when making charging decisions. Police officers, defence lawyers and victim-support organisations also rely on it. Guidance issued by the Crown Prosecution Service should explain what the law is, not what groups such as Stonewall, Galop and Gendered Intelligence would like it to be. 

Muddled guidance could have real and damaging consequences: genuine offences may not be prosecuted or people may face prosecution on the basis of an incorrect understanding of the law.

The guidance is also likely to influence sex education and guidance produced by other organisations for young people, and for those who identify as transgender. Young people who are experimenting with sexual relationships for the first time and who may believe that “you are who you say you are” are particularly at risk of misunderstanding the importance of sex to the validity of consent, and of becoming either victims or perpetrators. 

Our case includes a witness statement from Dennis Kavanagh of the Gay Men’s Network, who says that deception as to sex is a growing issue for male homosexual victims: 

“The practice of trans identifying females concealing their sex, colloquially known as ‘stealthing’, is a known issue in homosexual male spaces.“ 

He points at the guidance issued by ClincQ, Cruising: a trans guy’s guide to the gay sex scene, which encourages this – “Some guys [trans-identifying women] might not tell their sex partners.”

Kavanagh points out in his witness statement that deception as to sex has been identified by some trans-supporting lobby groups and charities as a target for reform with the ultimate aim of removing the right of the victim to obtain information about the sex of their potential partner prior to sexual contact. For example, Stonewall’s publication A vision for change: Acceptance without exception for trans people included as a goal:

“Judicial clarity of ‘sex by deception’ cases to define the legal position on what constitutes sex by deception based on gender, and to ensure trans people’s privacy is protected.” 

The CPS itself, as the principal authority responsible for prosecutions, should be unequivocal, precise and clear as to the centrality of biological sex to sexual orientation and therefore to consent to sexual activity, just as the law itself is clear on this point. 

Sex Matters is asking the court to quash the guidance, or to remove those parts of it that misstate the law.