Progress towards gender diversity on the UK’s highest court is in danger of being thrown into reverse, following the announcement that another female justice will retire shortly. Lady Black’s replacement could leave the supreme court with only one woman and 11 white men on the bench – a prospect that has triggered an urgent search for candidates to avoid that outcome. At the beginning of the year, the court’s president was Lady Hale, one of three women who sat alongside nine male justices. She retired in mid-January. Another female justice, Lady Black, has announced she will leave early next year. The only other female justice, Lady Arden, is due to step down in 2022. Responding to the news, Dinah Rose QC, who has often appeared before the supreme court, tweeted: “That leaves only one woman on the all-white court. Very disappointing. The court’s genuine desire to improve its diversity remains hamstrung by its appointments system, in my view.” Andrea Coomber, the director of the legal reform organisation Justice, said: “The small amount of progress made in respect of the gender diversity of our judiciary is fragile and, particularly at senior levels, the risk of regression high. “We are deeply concerned that the gender diversity of the supreme court could revert to where it was three years ago, with just one woman justice. We are equally concerned by the continued absence of any racial diversity on the court. “We therefore welcome the emphasis on diversity in the recruitment announcement, and we are pleased to see that applicants from a wide range of backgrounds are being encouraged to apply. It is regrettable that, due to the limited diversity of the court, the critically important appointment of a non-white justice may well come at the expense of the recent small gains in gender diversity.” Appointments to the supreme court are on merit. However, when two candidates are deemed to be equally well qualified, the selection commission can choose the one from a less well-represented background. Lady Hale has previously urged that the equal merits provision be employed at the beginning of the selection process rather than leaving it to the final stage. In a sign of the supreme court’s concern, it has dedicated a section of its website to promoting the vacancy. A pre-application webinar and a “familiarisation telephone call” are being made available to candidates, along with podcast interviews recorded by serving justices about their career path and the application process. Lord Reed, the president of the supreme court, has recorded a video message, saying: “We are hoping for applications from the widest range of applicants … and particularly from those who would increase the diversity of the court – not only in such obvious respects as gender and ethnicity but also in such matters as professional background and experience.” Improving gender and ethnic diversity among the judiciary has been recognised for some years as a pressing need if public confidence in the judiciary is to be sustained. Last week, the judiciary published an “inclusion strategy” in which the lord chief justice of England and Wales, Lord Burnett of Maldon, said: “A more diverse judiciary will capture talent that is currently lost to us and help cement the confidence of the public that the judiciary broadly reflects society.” In 2015, 25% of all court judges in England and Wales were women; that proportion has now risen to 32%. Over the same period, the number of judges from minority ethnic backgrounds has climbed from 6% to 8%. One aim of the strategy is to improve data held about the judiciary. Consequently, judges will be asked to define their socio-economic background. They will also be asked for more details of their ethnicity to “break down the broad category of BAME into different categories reflecting the different ethnic communities in England and Wales, to improve our method of measuring inclusion”. Training will also be given in recognising “the existence of implicit bias and how to employ mitigation strategies”.