A judge has ruled that an intervention by the UK government blocking plans to introduce gender self-identification in Scotland is lawful.
The Scottish Parliament passed legislation last year that would make it easier for people to change their legal gender.
The legislation would lower the legal age limit from the current 18 to 16 and remove the need for a medical diagnosis of gender dysphoria. It would also shorten the period required to live in a chosen gender from two years to just three months.
It received cross-party support in Holyrood, disregarding the concerns of feminists and Christian groups about the safety of women and girls, and protection of single-sex spaces.
In an unprecedented move, the Westminster government vetoed the legislation when Scottish secretary Alister Jack used a Section 35 order for the first time in January. This move stopped the legislation from receiving Royal Assent, the final step to becoming law.
This prompted Scottish First Minister Humza Yousaf to launch legal challenge in a bid to overturn the veto.
Ruling today, the Court of Session in Edinburgh rejected his legal challenge, which has cost the taxpayer £230,000.
The Scottish government has 21 days to lodge an appeal against the ruling.
Commenting on the judgment, Michael Veitch, Scotland Policy Officer at Christian policy group CARE, said: "Today's ruling is unlikely to be the end of the road in this complex legal battle, but it will be welcomed by a broad range of groups that fear the impact of a 'self-ID' system on child safeguarding, sex-based provisions, and the integrity of official data.
"We urge political leaders to give attention to legitimate and sincerely held concerns about the gender recognition legislation and related policies, and ensure a civil and respectful discourse that affords all parties the right to speak."
The Scottish secretary told STV News he was "obviously very pleased that the decision I took has been vindicated".
"I'm very pleased that the Section 35 order that has never been before is clearly cemented into the Scotland Act of 1998 and I'm pleased also that the judge agreed with me that there were adverse effects on GB-wide legislation relating to equalities," he said.
Polling by Panelbase for The Sunday Times in April found that 44 per cent of Scottish voters did not support the Gender Recognition Reform (Scotland) Bill, and that fewer than one in five (18%) supported mounting a challenge against the Westminster veto.
In separate polling by YouGove for The Times last December, two thirds of Scottish voters opposed the bill.
