A legal challenge has been lodged against the government's freshly introduced code of practice for the Equality Act, with campaigners moving to halt it the very day it became active.

The Good Law Project, a non-profit organisation known for taking legal action against the state, is seeking to overturn the guidance published by the Equality and Human Rights Commission (EHRC). The move has received backing from Labour MPs aligned with Mayor Andy Burnham, according to reports.

The newly implemented code clarifies that a service can only be considered single-sex under the Equality Act if it is accessed on the basis of biological sex. As a result, facilities such as toilets, changing rooms, hospital bays and refuges are to be designated according to a person's sex at birth rather than their self-identified gender.

The EHRC has stated that the guidance is a direct response to the Supreme Court's April 2025 decision, which concluded that references to "woman", "man" and "sex" in the legislation relate to biological sex as assigned at birth. The regulator has insisted that it is not introducing fresh legislation, but merely offering impartial and legally accurate clarification to businesses such as restaurants and leisure venues.

However, the Good Law Project contends that the advice is itself unlawful. It is supporting an unnamed transgender individual and a trans-inclusive organisation in bringing proceedings against the code. The challenge has also drawn support from backbench Labour politicians associated with Andy Burnham's camp.

Nadia Whittome MP, who previously spearheaded a parliamentary bid to block the code in June, expressed her opposition in a statement. She argued that the guidance would lead to the segregation and exclusion of transgender people, adding that it would invite "gender policing based on stereotypes" and was both harmful and unworkable. She noted that despite a quarter of MPs signing a motion against it, the code had been brought into force without any Commons vote.

Fellow Labour MP Richard Quigley also voiced support for the court action, describing the guidance as having generated "nothing but confusion and anxiety" and appearing contradictory even under minimal scrutiny.

Another backbencher, Kim Johnson, echoed those sentiments, endorsing the Good Law Project's warning that the guidance was "incredibly dangerous and likely to cause unlawful discrimination".

Political figures from other parties have likewise called for the guidance to be scrapped. Liberal Democrat MPs Vicki Slade and Tom Gordon are among those signalling their desire to see it withdrawn, while Green Party deputy leader Rachel Millward has also rejected the code. Millward warned that it left transgender people facing the genuine threat of being shut out of vital services and public areas.