The current policy of placing some trans-identifying male prisoners in women’s prisons is unlawful and puts the Prison Service at risk of discrimination claims.
This is the conclusion of an Opinion by equality law barrister, Ben Cooper KC and the public law barrister, Myles Grandison, published today by the Centre for Crime and Justice Studies.
The Opinion comes as the government publishes the long-awaited draft code of practice from the Equality and Human Rights Commission (EHRC), which, among other things, clarifies the legal basis for the operation of single-sex services. The code of practice follows a Supreme Court Judgment in April 2025, which clarified that, in law, ‘sex’ refers to biological sex, not gender identity, meaning that males who identify as women remain male in law.
The number of prisoners in England and Wales identifying as transgender has grown over recent years: from an estimated 207 in 2021 to 448 in 2025, according to the most recent figures available. Around 80 per cent of these – 276 – are male prisoners who identify as women, with the majority of these male prisoners – 245 – housed in men’s prisons. A smaller group of trans-identifying male prisoners, however, are currently housed in women’s prisons.
HM Prison and Probation Service (HMPPS) justifies this policy on the basis that the Prison Rules state only that “women prisoners shall normally be kept separate from male prisoners”. The “normally” in the rule allows, HMPPS argues, for some trans-identifying male prisoners to be housed in women’s prisons.
HMPPS also argues that the allocation of male prisoners to women’s prisons is only made after a rigorous assessment, covering issues such as the prisoner’s vulnerability, mental health state, and their history of living as a woman.
Earlier this week, however, the draft code of practice from the EHRC stated that single-sex services can only provided “exclusively to one sex”, adding:
If a service provider... admits trans people to a service intended for the opposite sex, then... it is not a separate-sex or single-sex service under the Equality Act 2010.
In their Opinion, finalised last month, Ben Cooper KC and Myles Grandison argue that it is necessary to run women’s prisons on a separate-sex basis in order to meet the needs and rights of female prisoners. This is because female prisoners are a minority, vulnerable group with different characteristics and needs from male prisoners, which could not be met if they were accommodated in mixed-sex prisons.
Women’s prisons, they further argue, can only lawfully operate as single-sex services on the basis of excluding all male prisoners. If, Cooper and Grandison note, “some trans-identifying male prisoners are allocated to the women’s estate, it then becomes very difficult to maintain a rational basis or justification for not accommodating other male prisoners (both trans and non-trans)”.
As a result, they add, the current HMPPS “policy of accommodating some trans-identifying male prisoners in the women’s estate... is unlawful” and is likely to give rise to sex discrimination claims. This includes:
- Unlawful direct sex discrimination against other (non-trans) male prisoners who may prefer to be accommodated within a women’s prison (for example, because they are vulnerable to violence and abuse in a men’s prison and would feel safer in a women’s prison); and
- Unlawful indirect sex discrimination and/or harassment related to sex against any female prisoners who feel that their dignity, privacy and/or sense of safety and security is undermined, or whose health and/or wellbeing is otherwise adversely affected, by being confined with a male prisoner.
In recent years, HMPPS has accommodated some trans-identifying males in E Wing at Downview prison for women and girls. Ministers are keen to stress that male prisoners in E wing are housed separately from female prisoners. The justice minister, Jake Richards MP, told the House of Commons on 13 April this year:
They are accommodated completely separately to biological women, in a discrete building behind a gated fence. Despite being on the site of HMP/YOI Downview, E Wing is not part of the general women’s estate. E Wing prisoners may only have access to the wider regime at Downview in limited circumstances, and only where this is supervised by staff and following a thorough risk assessment.
The Opinion, however, argues that this arrangement is “unlikely to be justified and is likely to give rise to unlawful indirect sex discrimination against any female prisoner who is adversely affected by being confined alongside such prisoners”.
Commenting on Ben Cooper KC and Myles Grandison’s opinion, our Director, Richard Garside, said:
There has been a lot of anger, toxicity and conflict over the policy of placing some male prisoners who identify as women in women’s prisons. We also recognise that this is a sensitive area of public policy, with prison staff, civil servants, politicians and their advisors holding a wide range of views and perspectives on this issue.
Whatever individuals’ personal positions may be, however, it is important that the Prison Service, and other organisations operating in and around prisons, do so in compliance with the law as it is.
We hope that this Opinion will be accepted as intended: as a helpful contribution to inform decisions that ensure that the Prison Service operates in line with the law.
Jo Phoenix, Professor of Criminology at the University of Reading, said:
I welcome this Opinion for its clarity around single-sex provision in prisons. In other sectors, case law has established that permitting trans-identifying males to use female space (like changing rooms) amounts to indirect discrimination because of the different and disproportionately negative impact on women of sharing intimate space with males. This impact is almost wholly a result of the pervasiveness of male violence in women’s lives.
We have known for nearly two centuries about the connections between women’s imprisonment and their experience of victimisation at the hands of men. Somewhere between 60 and 80 per cent of women in prison have been the victims of male violence. They are much more offended against than offenders. This was one of the reasons for single-sex prisons in the first place.
This Opinion works through what we know about the vulnerability of women in prison, the Equality Act 2010 and the Supreme Court ruling. The conclusions it reaches are simple and profound.
Placing males (no matter how they identify) in female prisons is likely to be unlawful direct and indirect discrimination.
This is not a matter of ideology. It is a matter of law.
