The UK’s Supreme Court has ruled that “man”, “woman” and “sex” in the Equality Act 2010 refer to sex, not self-ID or paperwork (gender-recognition certificates). This agreed with our legal interpretation. We have published new guidance and are in the process of updating our publications to reflect the judgment. We are also working to provide answers to the questions we're hearing from supporters and the media. We will publish these as soon as possible.

URGENT ACTION: email your MP today on the Data Bill

The Supreme Court has confirmed that “sex” in the Equality Act 2010 means, and has always meant, “biological sex”. The law is clear: single-sex services should operate on the basis of sex, not gender identity. 

But many organisations are now digging in and resisting complying with the law. Even those that want to do the right thing are confused and frightened. How can they be confident in treating people based on their actual sex when there is no way of accurately verifying that information? 

For decades public bodies have corrupted their own data, recording men as women (and vice versa) in healthcare records and identity documents. This has nothing to do with the Gender Recognition Act: it has simply been a matter of gender self-ID. While around 8,000 people have a gender-recognition certificate, an estimated 100,000 people have the wrong sex recorded by at least one public authority such as the NHS or Passport Office. 

The Sullivan Review included a legal opinion which said that such practices breach data-protection laws. Instead of tackling the issue, the government seems set on pushing ahead with new legislation that will build this historic mess into a brand new system of government-endorsed digital data verification. People will then be able to use online apps that carry a government trustmark to “prove” they are the opposite sex in order to access services and apply for jobs. 

The Data (Use and Access) Bill is being debated on Wednesday 7th May. Will you write to your MP TODAY?

What’s the problem?

The Data Bill will establish a new “information gateway” between public authorities and online apps which enable people to prove who they are and facts about themselves. If you want to see how this will work, try the Post Office’s Easy ID on your phone. 

It relies on data from sources such as the Passport Office and driving-licence authority as “proof” of sex. But these public authorities have not kept their data accurate. They allow men to be marked as “F” and women to be marked as “M”. 

Unless the Data Bill is amended to block inaccurate data sources from being used to “prove” sex, it will bake in these practices. Gender identity is not recognised in law, but the new law will allow it to erase sex in practice, and make it impossible to implement the Equality Act and protect single-sex spaces. This is gender self-ID by the back door.

The amendment to solve the problem

An amendment that would solve the problem (NC21 Directions to public authorities on recording of sex data) has been proposed by Dr Ben Spencer MP.

It is based on the principle that public authorities should not be allowed to provide digital “proof” of sex data unless they are able to do so reliably. Currently, just one source is accurate: the record of births held by the General Register Office/ National Records of Scotland (since this original source cannot be changed, even with a gender-recognition certificate). This is what should be used whenever accurate data about a person’s sex is needed.

You can read more about the amendment in our briefing.

Write to your MP!

The Data Bill and the amendment are being debated in the House of Commons on Wednesday 7th May. Please write to your MP today

Find your MP’s name and email address.

Put URGENT – for Data Bill debate on 7th May in the title.

Introduce yourself and mention if you’ve been in touch before.

Use our text as the body of the email:

I am writing to you as a concerned constituent to strongly urge you to support the proposed amendment (NC21) to the Data (Use and Access) Bill that seeks to ensure that digital verification services enable people to accurately verify their sex (such as for healthcare and single-sex services).

This is in line with the recent judgment of the Supreme Court in the For Women Scotland (FWS) case, which found that biological sex matters. It said that clear data is needed so that “the interests of biological women (or men) can be rationally considered and addressed” and so too can “the interests of trans people (who are vulnerable and often disadvantaged for different reasons)”. 

This amendment would support everyone’s rights, including transgender people. 

  • Everyone needs to have their biological sex recorded accurately where it is needed (such as for their own healthcare).
  • Providers of single-sex services and sports need to be able to accurately verify people’s biological sex to keep them safe and to avoid conflicts.
  • Providers of health and social care need to be able to accurately record people’s biological sex to keep them safe. 

There is no need to ask people invasive questions about their anatomy or to humiliate or discriminate against them to record their sex. The birth register is already an accurate source of information on sex. It is being digitised and could be used to verify sex for most people in the UK, with their consent. 

Please read this briefing from Sex Matters, a human-rights charity that intervened in the FWS case and was commended by the Supreme Court for its cogent argument, which provided focus to the meaning of sex in law: https://sex-matters.org/posts/publications/data-bill-amendment-nc21-briefing-for-parliamentarians

The Supreme Court judgment showed how important parliamentary clarity about legislation is in this important area. I urge you to study the issue you will be voting on.

Accurate data should not be compromised. This amendment would ensure that: 

  • people CAN prove their sex (as registered at birth) using digital verification services
  • people CANNOT falsify their sex using digital verification services. 

Other people may write to you making the opposite case, urging you not to support this amendment, saying that data on sex and gender identity should be muddled up together. If this happens it will lead to more conflict, more harm to both women and transgender people, more risk, more cost to the public purse and more court cases. 

Digital identity verification is privacy-protecting. Ensuring that the data is accurate will not force trans people to “out” themselves when their sex data is not needed (such as when proving their age or renting a car). It will simply enable everyone (whether they are trans or not) to share accurate, trustworthy information on their sex when that information is actually needed, including for their own safety and the safety of other people. 

I would appreciate a response setting out your stance on this issue.


It’s particularly powerful if you can say why this matters to you, so add your own words.

Put your full name and address, with postcode – your MP needs to know that you are in their constituency.

Send the email and then see if you can get others to do the same.

URGENT ACTION: I've emailed my MP today about the Data Bill – can you? Share on X