The first time the British government blocks a law passed by the Scottish Parliament on the grounds that it would have UK-wide effects, and what does it turn out to be? One making it easier for transgender people to change their legal gender, removing the requirement that the applicant be diagnosed with gender dysphoria and to have "lived as" the identified gender for two years.
The announcement was greeted with fury by Scottish Social Justice Secretary Shona Robison, who called the decision to block the bill "outrageous".
Arguing that the bill does not affect UK-wide equalities law, she said the "political" move demonstrated the UK government's "contempt for devolution".
"This is a dark day for trans rights and a dark day for democracy in the UK," she added.
The Gender Recognition Bill passed by 86 votes to 39 in the Scottish Parliament last month. It was not close. 2020s Britain: America, but just the bad bits, and poor as dirt.