FOR WOMEN SCOTLAND LTD V THE SCOTTISH MINISTERS [2025] UKSC 16.

A note from Sir Nicholas Mostyn

This note, written by Sir Nicholas Mostyn on April 25th 2025, provides further detail and context to the conversation (above) on Law & Disorder. That conversation, with Helena Kennedy and Charlie Falconer, was recorded on April 21st 2025.

The Equality Act 2010 prohibits various forms of discrimination, harassment and victimisation in defined areas. The prohibited forms are those that violate the “protected characteristics” . These are

• age

• disability

• gender reassignment

• marriage and civil partnership

• pregnancy and maternity

• race

• religion or belief

• sex

• sexual orientation.

What does “sex” mean in this context?

The Gender Recognition Act 2004 states in sec 9 that a person with a Gender Recognition Certificate (a GRC) becomes the sex stated in the GRC “for all purposes”. But this change is “subject to provision made by this Act or any other enactment or any subordinate legislation.”

Sam Fowles writing in the Guardian tells us that

Nobody thought that the Equality Act provided otherwise.

Until this decision the EA was interpreted simply: people who were born women, biological women, or who had a GRC, trans women, were women for the purposes of the Act.

It was this interpretation that was being challenged in the SC. Sam Fowles tells us:

In 2018, the Scottish parliament passed a law encouraging public boards to have 50% representation for women. For Women Scotland, a group that describes itself as “working to protect women’s rights”, asked the court to strike the law down because it included transgender women. There followed a series of legal challenges which eventually made their way to the supreme court. …

In its summary at [265] the court held:

… the provisions in the Act relating to sex discrimination, and especially those relating to pregnancy and maternity, and to protection from risks specifically affecting women, can only be interpreted as referring to biological sex. This interpretation does not cause disadvantage to trans people, with or without a GRC. They can invoke the provisions on direct discrimination and harassment, and indirect discrimination. An interpretation which includes them in the definition of man or woman is not required to give them those protections.

Definition of discrimination

Section 13 defines discrimination:

A person (A) discriminates against another (B) if, because of a protected characteristic, A treats B less favourably than A treats or would treat others."

The specified areas

• Services and public functions

• Accommodation

• Work

• Education

• Associations

• Transport

Conceptually, the scheme only applies to arrangements entered into by B voluntarily. It does not apply to prisons, for obvious reasons.

Exceptions and rules

There are some general exceptions to the general rule such as national security and sport (see below).

Then there are rules (including exceptions) specific to individual protected characteristics.

For example, there are rules that relate to people undergoing a sex change. Section 16 says that it is discrimination to treat someone less favourably at work because they are undergoing sex change treatment. There are comparable provisions for people who are pregnant or breast-feeding.

Services

There is considerable concern about the terms of Part 3 - Services and public functions in the light of the SC judgment.

The central provision of Part 3 is section 29, which says that a service provider must not discriminate either by not providing the service at all or by providing it on terms which are discriminatory, including terminating it.

This general rule is subject to a raft of exceptions in Schedule 3

It does not apply to

• Legislatures enacting legislation

• Any judicial function

• anything done for the purpose of ensuring the combat effectiveness of the armed forces.

• Activities of MI5, MI6 or GCHQ

• Aspects of:

• Education

• Heath and care

• Immigration

• Insurance and other financial services

• Marriage

• Television, radio and on-line broadcasting and distribution

• Transport

It is Part 7 of Sch 3 that is relevant- these are the exceptions where a service provider provides either Separate services for the sexes or Single-sex services

Separate services are allowed if a joint service for persons of both sexes would be less effective, and the limitation is a proportionate means of achieving a legitimate aim.

Single-sex services are allowed in certain circumstances (e.g. only persons of that sex have need of the service, or in hospitals) and it is a proportionate means of achieving a legitimate aim.

But what about trans people? Para 28 says there is no gender reassignment discrimination by X where X has provided separate services for persons of each sex; or has provided separate services differently for persons of each sex; or has provided of a service only to persons of one sex and whatever X has provided is a proportionate means of achieving a legitimate aim.

So, if X has provided separate male and female changing rooms and bans a trans woman Y from using either, this will not amount to discrimination however sex is defined provided that X can show that the measure was a proportionate means of achieving a legitimate aim.

Table showing swapping of labels

The EHRC

Pre the SC ruling the EHRC gave as an example the following permitted act of discrimination:

“a leisure centre introduces some female only fitness classes. It decides to exclude trans women because of the degree of physical contact involved in such classes.

It says that when reaching a decision

your approach must be a proportionate means of achieving a legitimate aim. This will depend upon the nature of the service and may link to the reason the separate or single-sex service is needed. For example, a legitimate aim could be the privacy and dignity of others. You must then show that your action is a proportionate way to achieve that aim. This requires that you balance the impact upon all service users.

The scale of “the problem”

So if all this could already be done, what was this decision about and why have people like JK Rowling celebrated so vehemently?

As of 2020, there were reportedly no trans women serving on public boards. Trans people make up around 0.4% of the over-16 population in Scotland. The chances of a biological woman losing a public board position to an equally qualified trans woman are nil.

So the actual impact of the decision is negligible. It is the collateral interpretation that is far more relevant

Hot topics

The subjects that seem to have attracted most attention are

• Prisons

• Changing rooms and lavatories

• Sport

Prisons

The Equality Act does not say anything about where a trans prisoner should be sent. In R (On the Application of FDJ) v Secretary of State for Justice (Rev 1) [2021] EWHC 1746 (Admin) Holroyde LJ said

“There is no statutory requirement that male and female prisoners be accommodated in different establishments, but rule 12(1) of the Prison Rules 1999 provides that ‘Women prisoners shall normally be kept separate from male prisoners.’"

Policy is governed by HM Prison and Probation Service (HMPPS) framework titled The Care and Management of Individuals who are Transgender (February 2023).

This says

Transgender prisoners are allocated to male or female prison estates based on comprehensive risk assessments. These assessments consider factors such as the individual's legal gender, anatomy, offending history, and the safety and welfare of all prisoners.

“transgender women (including those with GRCs) with birth genitalia and/or any sexual or violent offence conviction (see Annex D) or current charge should not be held in the general women’s estate, with exemptions recommended by a Complex Case Board (CCB) being referred to the HMPPS Director General Operations for consideration and the Secretary of State for Justice for a final decision. An agreed exemption must be in place before any allocation to the general women’s estate can occur.”

Exemptions: While the policy provides general guidelines, exemptions can be made in exceptional cases. Such decisions require approval from senior officials within the Ministry of Justice.

Specialist Units: If a transgender individual cannot be safely accommodated in either the male or female estate, they may be placed in a specialist unit designed to ensure their safety and the safety of others

It therefore does seem that a trans-woman who has undergone a sex change and who does not have a sexual or violent offence conviction will be held in a women’s prison.

Why are the trans women with birth genitalia or who have committed sexual or violent offences excluded from women’s prisons?

Presumably if they are in the former category (possessing birth genitalia) it is because their presence would cause the biological female prisoners to feel uncomfortable.

If they are in the second category (having committed a sexual or violent offence) presumably (and rightly) because they are considered to be a risk of committing a comparable offence on a biological woman prisoner.

I consider that in formulating this policy there is a danger of insufficient regard being given to the human rights of the trans-woman prisoner. A trans woman prisoner who is placed in an all-male prison is surely at very considerable risk of victimisation, abuse and assault.

If the reason is birth genitalia why the do the feelings of discomfort of the biological women prisoners trump the rights of the trans-woman prisoner not to be victimised abused and assaulted?

As to sexual or violent offences, why is it necessarily assumed that a trans woman prisoner who has committed such an offence is more likely than a biological woman prisoner to commit a comparable offence on another biological woman prisoner?

In 2023 there were 54 reported sexual assaults in women’s prisons, a 100% increase on the previous year. There were 990 prisoner-on-prisoner assaults of which 82 were categorised as serious. Why is it assumed that if a trans woman prisoner is placed in a woman’s prison the other inmates are at an increased risk of assault? Why does this assumption outweigh the risks that the trans-woman prisoner would face if placed in a male prison? On the facts the decision may be reasonable but surely there has to be a balancing of rights in each case where it is proposed to place a trans woman in a male prison.

Changing rooms

As explained above, the law has always allowed clubs to have separate changing rooms for men and women and also to exclude trans people from such changing rooms following the criteria set out above.

Yet, the EHRC has long campaigned for the law to be amended in the way that the Supreme Court has now done. It has said, for example (see [247]):

(6) Single-sex and separate sex services: Service-providers are sometimes all permitted to offer services to the sexes separately or to one sex only. For instance, a hospital might run several women only wards. At present, the starting point is that a trans woman with a GRC can access a 'women-only' service. The service-provider would have to conduct a careful balancing exercise to justify excluding all trans women. A biological definition of sex would make it simpler to make a women's-only ward a space for biological women.

This does not seem to be very logical. A biological definition of sex would not make it easier for a club to designate separate male and female changing rooms. They could do that anyway, obviously. It does not make it any easier to exclude, as a matter of law, a trans woman from a female changing room, for example. It just swaps the labels – see the table above

Sport

Section 195 deals with the fair participation of women in sport. It covers any sport game or other activity of a competitive nature where the physical strength and stamina or physique of average persons in one sex would put them at a disadvantage compared to average persons of the other sex as competitors in the activity. Invariably this is the case for women as regards many sports.

Section 195(1) says that a person does not contravene the Act so far as sex is concerned only by doing something in relation to the participation of another person as a competitor.

Section 195(2) says that a person does not contravene sections 29, 33, 34 or 35 (provision of services or accommodation) so far as gender reassignment is concerned only by doing something in relation to the participation of a trans person as a competitor which it is necessary to do to ensure fair competition or the safety of competitors in the activity.

Example

X, the organiser of the village games, treats Y, a trans woman with a GRC (originally biologically male), less favourably than she would treat Z (a biological woman) by excluding Y from the women’s boxing competition

Before the SC decision Y is treated as having the female sex and will be excluded as per the Table below. After the decision Y is treated as having the male sex and will also be excluded as per the table.

So, again, the labels are rearranged, but the result will be the same.

Conclusion

The effect of the ruling is, as a matter of law, to swap a number of the labels. As a complaint of gender reassignment discrimination is just as legally potent as a complaint of sex discrimination is hard to see what the furore is about.

But in many instances where a judgment is given by the top court the public interpretation is not concordant with the its legal meaning.

There is a public perception that the subtext of the SC judgment is that it is now much easier to discriminate against trans women by excluding them from services available to the public. The Chair of the EHRC, Kishwer Falkner, certainly thinks so, and revised guidance from that body is expected by July. She has said that said the NHS would need to change its rules on single-sex wards and her organisation would pursue the matter if it did not. As set out above, at [247] the SC sets out the view of the EHRC that in 8 areas there would be greater legal clarity if sex were defined as biological sex in the EA, and that such a definition “would make it simpler to make a women's-only ward a space for biological women”. But the change does not make it “easier” to establish women’s only wards. One of the grounds justifying the establishment of single-sex services are (a) “the service is provided for, or is likely to be used by, two or more persons at the same time, and the circumstances are such that a person of one sex might reasonably object to the presence of a person of the opposite sex” (Para 27(6)). At [217] the SC said :

“it is difficult to imagine how or in what circumstances it might be considered reasonable for a woman to object to members of the opposite sex where "the opposite sex" would include trans women without a GRC (who remain legally male) but not to "members of her own sex". This would arise if by operation of section 9(1) of the GRA 2004 the group of "members of her own sex" were to include biological men with a GRC, and so legally female who may be physically and outwardly indistinguishable from the former group of trans women without a GRC. While many women in a female-only changing room or on a women-only hospital ward or in a rape counselling group might reasonably object to the presence of biological males, it is difficult to see how the reasonableness of such an objection could be founded on possession or lack of a certificate. This is so especially when the distinction does not track physical appearance or presentation, and the woman is unlikely to have any information about the GRC at the point at which her objection might be raised. A trans woman with a GRC who presents fully as a woman may feel she is more likely to prompt objections from other users if she enters the men's changing room or other facilities than if she uses the women's changing room or facilities. But in facing that dilemma she is in the same position as a trans woman without a GRC. Although such trans women may in practice choose to use female-only facilities in a way which does not in fact compromise the privacy and dignity of the other women users, the Scottish Ministers do not suggest that a trans woman without a GRC is legally entitled to do so.

Consider a hospital that has only single sex wards, male and female. Consider first a trans woman with a GRC who presents as a woman (X) who has been admitted by the hospital. Before the SC ruling the NHS would have treated X as a woman and have placed her in a women-only ward. The biological woman in the next-door bed could not validly object to the presence of that trans woman. That trans woman is legally a woman and looks like a woman. If X did not have a GRC it is difficult to see how she could lawfully be placed in a women-only ward but if she was, she would be in the same position as the trans woman with a GRC.

Now consider a trans woman who does not present as a woman but has a very masculine appearance (Y). The next-door woman can reasonably object and the validity of that objection is not affected by the possession, or not, of a GRC.

Now consider a trans man who presents as a man (Z). Before the definitional change he would be placed on a men’s ward. If he had a GRC no objection could validly be raised by the next-door man. Likewise if he does not.

Now consider the position after the SC ruling. X cannot now be placed in a women-only ward, even though she has a GRC. She has to be placed in a men’s ward, where her presence might lead to objection from the man in the next-door bed, or perhaps insults and abuse. The same applies if X does not have a GRC. Y also has to be placed in a men’s ward but her masculine appearance should not lead to any objections. Z has to be placed in a women’s ward, where objection can validly be raised.

The definitional change does not “make it simpler” to make a women's-only ward a space for biological women. It just swaps the placement dilemma from one patient to another, as the following table shows:

But one has to wonder what the scale of the so-called problem is. What is the usage by trans women of these services? The actual number of trans women is tiny (0.4%) and even that is doubted as an accurate figure. How many violent/sexual trans women prisoners have been placed in a women’s prison since the adoption of the new policy? None. How many trans women gym users have been excluded from a female changing room? A handful.