Four trade unions that support the Labour Party will not attend its 2026 Women's Conference, because the party has decided to stop trans women from entering the main hall.

Unison, Usdaw, Aslef and the Musicians' Union said they will stay away from the conference, which takes place in Liverpool just before the main Labour Party conference in September 2026. The Metro first reported the boycott on 29 July 2026, with PinkNews following on 30 July (Metro; PinkNews).

Labour MP Kate Osborne said the same day that she would join the boycott. In a post on her official Facebook page on 30 July, Osborne said she would be "joining my union comrades" in staying away from the Liverpool event (Facebook).

The boycott goes back to a decision Labour announced in December 2025. The Guardian reported that trans women would be barred from the main part of the 2026 women's conference (Guardian). The ban covers the main hall but not the fringe meetings — the smaller, informal sessions that run alongside the official event. Labour said this is the least restrictive way to stay within the law while keeping the conference as open as possible.

The law in question changed in April 2025, when the UK Supreme Court ruled that, under the Equality Act, the word "woman" refers to biological sex. The Equalities and Human Rights Commission, the public body that oversees equality law in Britain, then issued guidance saying that a trans woman is a biological male who identifies as a woman and should not use single-sex spaces.

Labour cancelled the 2025 Women's Conference altogether right after the Supreme Court judgment. A leaked paper from Labour's National Executive Committee, the body that runs the party, said the conference should be delayed because the only legally safe option was to limit attendance to biological women. The committee then agreed that the words "woman" and "women" in party rules must be read as meaning biological sex.

The unions and the party have long disagreed on this issue. Unison's policy says trans women are women, trans men are men, and non-binary identities are valid. The union is campaigning for the law to be changed to match its position. The BBC understands that the ban goes against long-standing policies on trans inclusion in most Labour-affiliated unions, and that a larger boycott could follow.

In the past, Labour let people self-identify, which meant trans women could attend the women's conference and take part in all-women shortlists — the system Labour uses to pick candidates in some seats to get more women into Parliament. The annual conference brings together hundreds of women, including MPs, councillors and party supporters.

The broader context is a party caught between a legal duty it says it cannot avoid and a union movement whose policies were written when self-identification was the normal practice in the party. The leaked advice paper made clear that Labour's lawyers could see no legal middle ground: either delay the conference indefinitely or restrict it to biological women. The compromise, limiting only the main hall while keeping fringe meetings open, has not satisfied the unions, whose policies explicitly say trans women are women.

The immediate question for Labour is whether the four unions that have pulled out remain alone, or whether the BBC's reporting on wider union feeling is right and more follow. The conference depends on union delegations for both attendance and voting weight, so a larger walkout would weaken it. Osborne's decision to side publicly with the boycotting unions brings the dispute into Parliament, rather than leaving it as an internal party matter.

The episode also shows how quickly the Supreme Court ruling is changing how institutions across the Labour movement operate. Less than sixteen months separate the April 2025 judgment from the September 2026 conference. In that time, the party has gone from cancelling the event, to a leaked legal assessment, to a policy that its own affiliated unions say goes against their rules.