SHE has become the pin-up girl – or, for some, boy – of Scotland’s culture wars. Isla Bryson’s picture has rarely been off the front pages of the nation’s tabloids since she was convicted of double rape last month.

Usually the 31-year-old beauty student is shown clutching a pink phone to her ear under a shock of blonde hair. Her nails are long and manicured, her face carefully made up. But sometimes editors choose to print old photos of Bryson, when she was known as Adam Graham and had a shaved head and face tattoos.

This rapist – court reports referred to “her penis” – was initially remanded in custody to Scotland’s only women’s prison, where she would have been segregated. Cue hell’s fury.

Scotland’s first minister, Nicola Sturgeon, quickly ordered Bryson to be locked up in a men’s jail, again separately from the general population. 

This was either a “screeching U-turn” or the result of a pragmatic risk assessment, depending on who you choose to believe.

This row came after weeks of sizzlingly high-voltage politics on when and how Scots should be able to change their official gender. 

Just before Christmas Holyrood, the country’s parliament, passed a bill allowing what is called self-ID. 

This, supporters say, is a modest reform designed to help transgender people update their paperwork so core documents, such as their birth certificates, match their lived reality without getting a doctor to sign off.

Critics argued that the bill would embolden predatory men who might change their legal gender to access women-only spaces. 

Strictly speaking, the proposed legislation would have made little legal difference: trans women have never been asked for a birth certificate to enter the Ladies. But the self-ID bill has acted as a lightening rod for many wider anxieties and, some add, prejudices.

Similar laws have been in place elsewhere, including the Republic of Ireland but not Northern Ireland or England and Wales, for some years. 

Scotland’s was six years in the making and involved two lengthy and laborious public consultations. It was a manifesto commitment of four out of the country’s five main parties and had – when first suggested – also been the favoured course of then prime minister Theresa May.

So you might think this would be a very straightforward piece of legislation. Nope. The bill passed, easily. But it also sparked the biggest SNP backbench revolt in years, with one junior minister resigning.

Trans-ID, and trans rights in general, cuts right across feminism Scottish constitutional politics. It has made allies of Labour, the Lib Dems, most mainstream nationalists and some liberal Tories. 

And it has created a seemingly unlikely partnership of Ms Sturgeon’s arch-nemesis and pro-independence predecessor, Alex Salmond, and the most Union-Jacky unionists. 

The British Government is not happy. Last month Alister Jack, the Scotland Secretary, announced he would block the bill, saying it clashed with UK equalities laws. 

Now this has never happened in the history of Devolution. The Scottish Government has said it will test his decision in court.

There are definitely Conservatives – big c and small – and a whole range of others who have serious concerns about how women’s rights and trans rights clash. That is why the Bryson case has made such headlines: there are a good few people – Ms Sturgeon included – who think her right to identity as a woman is trumped by the the rights of female prisoners to safety.

But there is more to Mr Jack’s veto than concerns about the merits of the bill. The politician has made no secret that he dislikes the idea of the UK as a multi-national state, of talk of “four nations”. 

In the Commons he agreed that British citizens should have the same rights and responsibilities wherever they are. Conservative MPs, by way of illustration, equated the decision to stop Scottish gender self-ID with recent moves to bring Northern Irish law on abortion, the age of consent and gay marriage in to line with the rest of the UK.

And so the SNP and its allies – across the usual constitutional divide – finds itself facing up to the UK Government in a legal and political battle. 

Most Nationalists – and a number of unionists – see this as a fight for the very soul of Devolution and legislative diversity in the UK. Some nationalists and most Conservatives see Ms Sturgeon as “woke” and out of touch with public unease. 

Some more extreme voices have started referring the SNP as a “nonce” party and implied all trans women are groomers. It is getting nasty. Hate crimes against trans people have tripled since Scotland first started considering gender self-ID.

The hard and far right – as on the continent and in the US – has capitalised on the row. 

Ms Sturgeon caused uproar when she said some – but not all – opponents of self-ID were transphobic and also racist. She was right. Some are. But many are not and they took her words as a smear.

It is hard to overstate how worked up some people on both sides of the debate have become. There have been convictions for threatening behaviour against prominent critics of the legislation, such as the SNP MP Joanna Cherry.

Trans activists held up a cardboard placard in Glasgow calling for their opponents to be “decapitated”. 

Sections of the LGBT community, including some of the most marginalised in our society, are hurting and lashing out. So are women whose fear of “men" in single-sex spaces is not theoretical.

Social media has not helped. JK Rowling, the Harry Potter author, has 14m followers on Twitter. The one-time major funder of the campaign to keep Scotland in the UK is a major voice against self-ID. She has focused her ire on Ms Sturgeon rather than unionist supporters of the bill. The writer posted pictures of herself wearing a t-shirt calling the first minister the ‘destroyer of women’s rights”.

There are unionists who think this row will derail Ms Sturgeon’s independence bid. They definitely want to break social conservatives out of the broad alliance for a sovereign Scottish state. But there is more to this issue that flag politics: culture wars are raging everywhere and there is no reason to think they will stop in Scotland.