A group of peers is at the centre of a House of Lords plot to derail guidance protecting women’s single-sex spaces, leaked documents have revealed.

The group, which includes a former head of Stonewall and one of its founder members, is seeking to scupper rules drawn up by the Equality and Human Rights Commission (EHRC) by delaying the government’s process until a new chair of the regulator is appointed.

A source told The Times that Lord Collins of Highbury, the government’s equalities spokesman in the House of Lords, had been involved in “strategy development” with the group. Neither he nor the Office for Equality and Opportunity has denied the claim, repeatedly refusing to say whether he had met or been contacted by the group.

The women’s and equalities minister, Bridget Phillipson, received the updated rules last month.

They are understood to restrict the ability of trans people to access services of their chosen gender and follow an April Supreme Court ruling to clarify that, under the Equality Act 2010, the term “woman” refers to biological sex.

Collins told the Lords this week, during a debate on the delay to the laying of the guidance, that “we have to consider this matter seriously and take into account all possible risks and issues to ensure that we have a legally proofed code that is understood by everyone”.

He said there had not been a “delayed process” and that Phillipson would need time to “take a fully informed decision”.

A protester holds a large trans pride flag outside Downing Street during a demonstration in support of trans rights.

Trans protesters outside Downing Street

VUK VALCIC/SOPA IMAGES/LIGHTROCKET /GETTY IMAGES

Under the Equality Act, once the code is approved, it will be laid in parliament for 40 days before it becomes statutory. There is no requirement for politicians to be able to debate the code, although some MPs and peers, including Phillipson’s deputy leadership rival, Lucy Powell, said they should be able to do so.

The guidance was updated after the Supreme Court ruling that said that a woman was defined biologically in reference to the Equality Act and that this definition applied to any organisation that provided services to the public.

It has not yet been laid in parliament, however, and Phillipson has been accused of delaying its release in a bid to save her Labour deputy leadership campaign, which she has denied.

It is understood the group of peers met in parliament on Wednesday after a debate in the Lords on the guidance.

Among those in the group is Baroness Hunt, who previously led Stonewall’s “no debate” approach on transgender rights. The group, calling itself “friends and allies”, believes “the EHRC is at risk of being pulled towards more restrictive positions”, documents showed.

Baroness Ruth Hunt in a plum suit, white shirt, and black tie.

Baroness Hunt led Stonewall’s “no debate” approach on trans rights

ROGER HARRIS PHOTOGRAPHY

One document, seen by The Times, described the EHRC guidance as “of critical importance” in shaping how inclusive public and private sector organisations could be. It warned that the EHRC’s interpretations carried “weight far beyond the courtroom”.

The strategy outlined plans to present the group as “constructive partners” while pushing for additional due diligence on the guidance, which critics suggested was a move designed to delay implementation.

It said they would push the government to “use the forthcoming appointment of a new chair and additional commissioners as an opportunity to restore balance and credibility to the EHRC’s leadership”.

Baroness Falkner, the current chair of the EHRC, who has advocated for women’s rights in the debate on gender, will step down at the end of November. Her replacement, Mary-Ann Stephenson, has already faced criticism from transgender activists over her gender-critical views.

The EHRC is also due to appoint at least three new commissioners in the coming months and the document suggested the group would attempt to lobby the watchdog’s new chair and commissioners to water down its guidance.

The strategy said this would create “risk and opportunity”. It said: “With the right leadership and balance of commissioners, the EHRC can be pulled back to the middle ground: credible, authoritative and committed to upholding equality for all communities.”

It also identified “opportunities over the next parliament”, including pressuring the government to “undertake thorough consultation and legal due diligence before the EHRC’s draft statutory guidance is laid before parliament”. The document warns that without this, ministers risk being “saddled with a document that is both harmful in practice and vulnerable to challenge in the courts”.

Peers were encouraged to table written and oral questions to ensure ministers confirm that the guidance has undergone proper consultation, legal review, and equality impact assessments, and to raise concerns about “balance and credibility” in upcoming EHRC appointments.

The group includes a number of peers including Hunt, the Stonewall co-founder Lord Cashman, the former Labour health minister Baroness Thornton, the former Scottish Labour leader Baroness Alexander, the Lib Dem peer Baroness Barker, Baroness Chakrabarti, Baroness Ramsey and Baroness Donaghy.

All of those mentioned were contacted for comment. Government sources insisted the group would have no bearing on the timing of the guidance being laid in parliament.

Claire Coutinho, the shadow equalities minister, said: “It’s outrageous, though hardly surprising, that peers with links to Stonewall are trying to delay this crucial guidance. Women and girls deserve protection, not dither and delay.

“Bridget Phillipson needs to get on with the day job and publish the EHRC guidance immediately.”

Maya Forstater, the chief executive of the charity Sex Matters, said it was “devastating to see a group of peers in the House of Lords plotting to thwart the law”.

She said: “The Supreme Court has spelled out what the Equality Act means, and that women’s rights depend on recognising that everyone is either male or female, and no one can change sex. There is nothing kind about this wicked attempt to put trans identifying men’s wishes ahead of the privacy, dignity and safety of women and girls.

“The government must stamp on this disgraceful behaviour and get on with confirming the EHRC Code of Practice and ensuring compliance with the Equality Act across the country.”

A government spokesman said: “The government is considering the draft updated code and, if the decision is taken to approve it, the minister will lay it before parliament.

“The proposed Code of Practice is over 300 pages long, so it is important that the correct process is followed.”

The EHRC has been contacted for comment.