A Labour source said following the ruling that Sir Keir, who previously said women could have a penis, "hauled the Labour party back to the common sense position".

Ms Duffield said: "We've already heard the Labour Party sort of trying to backtrack and pretend that they were always on board, which is obviously not the case.

"I hope all politicians understand that the law has to be stuck to here."

Asked whether she thought there might be a broader change in the way the party approaches issues of gender following the ruling, Ms Duffield said: “Possibly, I mean I’d like to think so.

"Certainly, women like me and all of the gender-critical so-called feminists who have been very silent, very quiet in Labour and haven’t supported me, perhaps they’ll feel braver now about speaking up.

“I’m starting an all-party parliamentary group on women’s rights with the Women’s Rights Network, and perhaps people should pressure their Labour MP to join that now.”

In 2020, Ms Duffield said on Twitter that “only women have a cervix”, something Sir Keir later said was “not right”.

In 2023, Ms Duffield wrote a piece for the UnHerd website accusing the party of believing the “transgender debate is nothing more than a culture war issue”, and claiming that her treatment by Labour reminded her of a former abusive relationship.

“When I come home at night, I feel low-level trauma at my political isolation,” she wrote.

Sir Keir said he wanted to see “respect and tolerance” in response to her comments.

The Prime Minister was asked repeatedly about his position on the matter in opposition.

In 2023, Sir Keir told The Sunday Times that for “99.9%” of women “of course they haven’t got a penis” but later that year he told BBC Radio 5 Live: “Firstly, a woman is an adult female, so let’s clear that one up."

In April 2024, he said Ms Duffield was right to say “only women have a cervix”.

He told ITV: “Biologically, she of course is right about that.”