Sex Matters blocked from bringing challenge over trans inclusion at Hampstead Heath ponds

The High Court has refused gender-critical non-profit Sex Matters permission to challenge the City of London Corporation (CoCL) over trans inclusion at Hampstead Heath ponds.

The ‘gender-critical’ campaigning group, that is supported by notable figures like JK Rowling, sought to bring legal action against the CoCL following the outcome of the controversial Supreme Court ruling on the legal definition of sex, which decided for the purposes of the 2010 Equality Act “sex” refers to “biological sex” only and specifically excludes trans people.

Opened in 1926, Kenwood Ladies’, Highgate Men’s, and Hampstead Mixed ponds in the north London beauty spot have long been inclusive of trans people, with the CoCL formally acknowledging trans people’s right to swim in the single-sex ponds back in 2019.

The legal decision comes on the same day that the results of consultation carried out by the CoCL into access to the ponds as single-sex spaces showed nearly nine in 10 people support trans inclusion.

In June of 2025, Sex Matters wrote to the CoLC warning that if the trans-inclusive policy was not changed, to make the pond single-sex only, the group would begin legal action “over its failure to take heed of the Supreme Court’s judgement”.

The CoCL, however, stated the ladies’ pond was not a single-sex space “precisely because trans women are permitted to access the swimming facilities” and therefore the “corporation recognises, following the Supreme Court’s ruling, that it is not providing single-sex facilities as defined within the [Equality Act]”.

The CoLC went on to say the Supreme Court’s understanding of “woman” and “man” as “biological” terms were not the same as how they saw them, and such terms “must be read in light of the access arrangements in place at the ladies’ pond, pursuant to which both trans women and biological women have been permitted to access the pond for many years”.

Sex Matters in turn accused the CoLC of “trying out an extraordinary manoeuvre”, with the group’s founder, Maya Forstater, telling The Times it was “nothing more than linguistic trickery”.

“The corporation claims that, because it chooses to define “women” and “men” according not to biological sex but to who wants to be referred to as ‘she’ or ‘he’, the Supreme Court judgement doesn’t apply,” Forstater said.

“Neither Hampstead Heath nor the City of London Corporation are sovereign entities that get to make their own laws.”

In a ruling throwing out Sex Matter’s legal action on Thursday (29 January), Mrs Justice Lieven set out that the organisation bringing the challenge to the High Court is not the “appropriate forum” for the matter and instead concerns about sex discrimination at the ponds should be raised on an individual basis via the County Courts.

“In my view the more appropriate person to bring this claim is an individual who says that they have been discriminated against by decisions about access to the ponds,” Lieven wrote in the legal decision.

She added there are “a number of features of this case which point towards one or more individuals being the appropriate claimant and the County Court being the appropriate forum”.

“The Claimant submits that it would not be able to bring a challenge in the County Court because it is a group not an individual,” Lieven went on to outline. “However, in my view that supports the Corporation’s argument that judicial review is not the appropriate remedy.

“The Act envisages cases brought by individuals in the County Court, in a forum where facts can be fully considered and appraised.

“The fact that the Claimant cannot do so merely reinforces the conclusion that this is not the appropriate forum.”

Following the outcome, the CoLC said via a spokesperson: “We note the Court’s decision. This case has required significant time and resources which could otherwise be focused on managing Hampstead Heath as a charity and providing high-quality public services.

“We have now published the results of a consultation on future access arrangements at the Heath’s bathing ponds.

“The findings will be presented to City Corporation committees which will consider them alongside legal duties, equality impact assessments, safeguarding responsibilities, and operational considerations.

“In the meantime, the current admission rules will remain in place until a final decision has been made by Members.

“Further announcements will be made in due course.”

In a statement published in response to the outcome, the Good Law Project’s trans rights lead, Jess O’Thomson, said: “Despite their supposed victory in the Supreme Court last April, anti-trans campaigners like Sex Matters have encountered failure after failure in their attempts to use the law to bully trans people out of public life.

“The reason for that is clear – as the overwhelming support for trans inclusion in the City of London’s consultation shows, people in this country want to be inclusive, and trans people have been welcomed in these spaces for decades.”

A spokesperson for the Trans Solidarity Alliance said: “It’s a shame that yet more public money has had to be spent defending against endless lawfare from a vocal, well-funded minority trying to force trans people out. 

“Trans inclusion is the norm across the country, and this government needs to act to ensure clarity and confidence for service providers to continue this without leaving them at risk of expensive litigation.”