Hampstead ponds: we have filed our case!

Sex Matters has filed its claim to the High Court seeking permission for a judicial review of the decision to continue to operate the men’s and women’s swimming ponds on Hampstead Heath on the basis of gender self-identification. 

Today we are publishing the facts and grounds of the case, as well as Maya Forstater’s witness statement, which refers to dozens of accounts from other women who swim at the ponds. Many wrote to us about why Kenwood Ladies’ Pond matters to them. As one said:

“It’s hard to describe the sense of calm joy I feel as I walk down the path and catch my first glimpse of the pond. Whatever the weather or season, the pond is tremendous, enabling a sacred immersion with nature which most of us London dwellers aren’t lucky enough to enjoy the rest of the time. So much life is here.

“The pond is magic, it’s a private haven, not easily visible from outside and it’s just for us. Women. Or rather it should be.”

But this case is not merely about a much-loved swimming spot in London. The central issue is whether service providers in general may lawfully permit people to access otherwise single-sex spaces of the opposite sex on the basis of transgender identity. 

The Supreme Court has made clear that the concept of “sex” in the Equality Act 2010 refers to biological sex, and that lawful single-sex services provided for under Schedule 3 of the Act are based on biological sex. 

But the City of London Corporation, which manages Hampstead Heath, responded to the judgment by doubling down on its policy of gender self-ID. Many other service providers are saying that they don’t understand the law and need more guidance. 

On 25 July 2025 the City of London Corporation put up new signage saying:

“Those who identify as women are welcome to swim at the Kenwood Ladies’ Pond. The Ladies’ Pond is open to biological women and trans women with the protected characteristic of gender reassignment under the Equality Act 2010.” 

Similar signs have gone up at the Men’s Pond. 

We argue that these rules are unlawful. We say they constitute:

• direct sex discrimination against both women and men, by operating outside of Schedule 3 exceptions for single-sex services
• direct / indirect sex discrimination against women in particular because women are at greater risk of suffering detriments to their privacy, dignity and safety. 

Many women have told us that since the self-ID policy was adopted in 2019, they no longer feel safe at the Ladies’ Pond or have self-excluded. One woman, who asked to be referred to as “Cathy”, said:

“I used to love going to the Ladies’ Pond at Hampstead Heath. However in the last few years I’ve felt very uncomfortable knowing that male bodied people are going there. It feels creepy to be sitting on the grass knowing there is a man next to you.”

Another, referred to as “Frances”, who is a registered disabled pensioner, has been using the Ladies’ Pond since 1984. She said:

“I now no longer swim at the ponds as I feel completely unsafe in enclosed spaces when men/naked men are known (and encouraged) to be in the vicinity. I am short-sighted – so seeing through the steam in the changing-rooms in the winter or who is on the meadow in the summer is difficult when I am showering or drying myself. I feel threatened by the known presence of men in our space.”

Some women told us about upsetting experiences when encountering men who have been allowed to use the Ladies’ Pond, and feeling unable to complain or getting nowhere if they do: 

• Josey and Issy describe an incident in June 2025, when they encountered a trans-identifying man in the meadow and challenged him. They were reported to the lifeguards, who said “all women are welcome.” 
• ⁠Marilyn describes three occasions of seeing men at the Ladies’ Pond in 2021, and being told “that’s a woman” when she complained. She describes an experience in 2024 when she was showering naked at the outside showers and a man stood between her and her towel looking at her. She reported this as voyeurism to the police and raised a concern with the Kenwood Ladies’ Pond Association. 
• A woman referred to as “Alice” told us about encountering a trans-identifying male swimmer in the ladies’ showers, facilitated by the stewards. She complained to the City of London Corporation and was told this was within its inclusion policy.
• A GP told us that in July 2019 she saw a man in a tight-fitting bikini bottom visibly displaying his male genitalia being helped by a group of women bathers to fit a bikini top. He entered the women’s changing room and stood staring at a group of naked teenage girls. She reported her concerns to the lifeguards, who said the person was entitled to be there.
• Sarah encountered a trans-identifying man in the showers and changing room in September 2023. 
• Mary encountered an elderly man asking young women to fasten his bikini top and then asking questions about nudity in the showers. 
• Valerie saw a young man with a full beard sitting in the meadow and felt she could not go and complain to the lifeguards.
• Emily said that in July 2025 there was a young man in a dress and makeup at the ponds.
• “Frances” said that in spring 2025 her neighbour saw a topless male in men’s swimming shorts with a young woman companion in the Ladies’ Pond. Her neighbour didn’t think she could complain. 
• Carol said she stopped going to the Ladies’ Pond three years ago, after seeing a man in a skimpy bikini rubbing himself and staring at women. 
• Amanda said that in 2018 she encountered a large naked man who came into the women’s showers when she was naked and vulnerable. She told the lifeguard, who said the man identified as a woman.
• Beverley complained in 2024, after noticing a topless man in the meadow taking photographs of young women. The lifeguard told her he was a trans woman. She reported the incident to the police and to the City of London Corporation.

We are asking the court for a declaration that the rules that allow men into the Ladies’ Pond are unlawful, and for an order quashing the decisions and the admissions rules. This would return the ponds to being single sex, and make clear to other service providers that following the law is not optional. 

A judgment in this case has the potential to bring much-needed clarity more broadly, to the benefit of the large number of duty-bearers (including small businesses) that provide single-sex services and wish to operate lawfully and without risk of claim. It will make clear the practical consequences of the Supreme Court’s decision in a concrete factual situation.

Now that the claim has been sealed by the court and served on the City of London Corporation, it has 21 days to reply with Summary Grounds of Defence. Sex Matters will then have another 7 days to file a reply. After that the court will consider whether we have permission to go forward to a full hearing of the case. 

Thank you to everyone who provided their experience for the witness statements. 

Our legal team are Tom Cross KC of 11 KBW and Sarah Steinhart of Doughty Street, with solicitor Sasha Rozansky of Deighton Pierce Glynn.

We have increased the stretch target for the crowdfunder to £65,000, for the next stage (and now with a King’s Counsel on the legal team). Please donate (and thank you to everyone who already has!)