Ministers defend claims they acted unlawfully by changing the definition of 'woman'

But the decision has been challenged by the feminist group For Women Scotland which says the legislation is unlawful and questions the Scottish Government view that "men who self-identify as women are female", and that that will be the basis of future policy.

It is contesting the legality of the 2018 Gender Representation on Public Boards (GRPB) Act, and what it called the redefinition of the word woman to include people who had not changed their legal sex to 'female' using a Gender Recognition Certificate (GRC).

The group says ministers were acting outside their legislative competency under the Scotland Act 1998 and in contravention of the UK Equality Act of 2010.

Ministers defending the challenged in the Inner House of the Court of Session - Scotland’s highest civil appeal court - say an amended Scotland Act 2016, permits the Scottish Parliament to legislate on "equal opportunities so far as relating to the inclusion of persons with protected characteristics in non-executive posts on boards of Scottish public authorities with mixed functions or no reserved functions".

Ruth Crawford QC, acting for Scottish ministers told the judges that the legislation was lawful saying: "It's within the legislative competence of the Scottish Parliament to legislate as it will within the terms of the public board exception."

She added: “I invite the court to refuse this motion.”

The Scottish Government has previously successfully defended a judicial review on its decision to include trans women in a new law to increase the number of women on Scotland’s public boards.

The aim of the GRPB act was to improve the gender representation on the boards of Scottish public authorities (SPAs) saying that 50% of non-executive members should be women.

READ MORE: Scots ministers accused of unlawfully changing the definition of 'women' in court challenge

But the definition of woman was changed from “a female of any age” – as it is defined in the Equality Act – to include a “person who has the protected characteristic of gender reassignment”.

People who hold a gender recognition certificate (GRC) have legally changed their sex, but For Women Scotland said the Scottish Government had gone further so that “woman” also includes those who do not have a GRC.

And they say that in equalities legislation the term 'woman' meant only biological women and the Scottish Parliament had no power to alter that because it was a reserved matter.

They also say that by treating biological and transgendered women in the same way, the 2018 Act went beyond what was permitted by the European Convention on Human Rights (ECHR).

And they say that while the new law was intended to address historical under-representation of women on public boards - it had set out a "dangerous precedent" of redefining women as those who the Equality Act 2010 would characterise as male, but who may self-identify as female.

They say the redefinition goes "against the very grain" of the Equality Act and decades of anti-discrimination law.

In a Court of Session ruling in her Court of Session ruling earlier this year, judgement Lady Wise ruled the government had acted lawfully under a “specific power” that enabled it to take equal opportunities measures and had not breached the UK Equality Act.

But For Women Scotland have taken the issues to the Inner House of the Court of Session - Scotland’s highest civil appeal court.

Aidan O'Neill QC, for For Women Scotland has told the court the GRPB legislation was unlawful because it undermined the rights of ‘biological’ women.

A panel of senior judges - Lady Dorrian, Lord Malcolm and Lord Pentland will is to consider its decision in a case brought by an organisation called For Women Scotland.

Lady Dorrian said the court would issue its decision in the near future.

She added: “We will take time to consider our decision.”