In comments defending crime commissioner Lisa Townsend after she faced complaints for criticising gender self-identification, Rowling wrote: “I don’t think our politicians have the slightest idea how much anger is building among women from all walks of life at the attempts to threaten and intimidate them out of speaking publicly about their own rights, their own bodies and their own lives.”

Sir Keir said his claims on the definition of “woman” were based on the “combined effects of the 2004 [Gender Recognition] Act and the 2010 [Equality] Act”, but campaigners have argued in the past that these laws do not support the claim that “trans women are women”.

It has been argued that the Gender Recognition Act does not allow transgender people to self-identify as women, but offers those with gender dysphoria the opportunity to gain legal recognition as the gender they prefer. Rather, the 2010 Act simply guards those undergoing any form of gender reassignment from discrimination.  

But it has been argued that this does not mean such people are legally treated as “women” when it comes to single sex-services, and that the current legal position is that they can be barred from women-only services on the grounds of their biological sex.

A government statement confirmed this in 2018, stating: “It will still be possible to exclude individuals with the protected characteristic of gender reassignment from single or separate sex services.”