The Harry Potter author is an outspoken gender critical campaigner and slammed the First Minister for claiming that plans to strengthen women’s rights across the UK was an attack on devolution.

Scottish National Party Leader John Swinney

John Swinney has been blasted by JK Rowling after the First Minister opened up the row over gender once again. He was accused of declaring that women’s rights “undermined devolution” as he hit out at Tory plans to amend the Equality Act to ensure the safety of women’s only spaces and events.

Equalities Secretary Kemi Badenoch has vowed to define the protected characteristic of sex in the UK-wide legislation as “biological sex” and would move to ensure that gender recognition would be a matter reserved to Westminster to allow no cross-border issues when it comes to accessing female only services.

It means that the Scottish Government’s controversial Gender Reform Recognition Act would be axed completely. It would allow trans people to legally identify as the opposite gender without the need of a medical certificate if they live that way for a certain amount of time.

The bill’s passage through Holyrood proved to be contentious, with campaigners claiming that predatory men can take advantage of this to make women feel unsafe. It was ultimately blocked by Scotland Secretary Alister Jack, with Ms Rowling one of the most outspoken people against it.

But Mr Swinney has been outraged by Ms Badenoch’s plans, and labelled it a “deliberate strategy to undermine the powers of the Scottish Parliament.” He told journalists: “This is just another step in the Conservative attempts to erode the powers of the Scottish Parliament. It’s been going on for some time.”

He pointed to Brexit and the Internal Market Act as weakening Holyrood’s powers and added: “I want the Scottish Parliament to be a parliament that can address all of the issues that affect the lives of people in Scotland. So, what the Conservatives are doing today is part of a deliberate strategy to undermine the powers of the Scottish Parliament.”

But his comments were lambasted by the Harry Potter author who took to social media to say: “When exactly in the 1997 devolution campaign was it mentioned that we were also voting to reclassify ‘woman’ as a nebulous collection of stereotypes that men can identify in and out of?”

Columnist and former Edinburgh councillor Susan Dalgety added: “Women’s rights undermine devolution says Swinney. What an absolute plonker.” Ms Badenoch said that a future Tory government would ensure that gender recognition be reserved to Westminster.

She wrote: “A permanent solution is required to stop devolved governments messing around in this space. We are one United Kingdom and it is impracticable for gender recognition regimes to vary in different parts of the country. So, we will also legislate to establish that gender recognition is a reserved matter.”

Scottish Labour leader Anas Sarwar criticised this position, calling it a “dead cat” policy, and an attempt to relight the “culture war.” But his Tory rival Douglas Ross welcomed the news, pointing out that Labour voted with the SNP on the controversial proposals at Holyrood.

He said: “I don’t want to see a repeat of the situations we’ve had here in Scotland such as the Isla Bryson scandal or the SNP’s attempts to pass the Gender Recognition Reform Act, which were clearly very controversial, but also ultimately did not succeed because of the court case between the UK and Scottish governments.”

“And I also think the question would be, if you don’t support this, why should women in Scotland have fewer protections than those elsewhere in the United Kingdom?”