LONDON – Thousands of trans rights protesters gathered in central London on Saturday, days after the U.K.’s Supreme Court ruled that a woman is someone born biologically female and that transgender women are excluded from that legal definition.

With unease growing over what the ruling means for the rights of transgender people, protesters came together for what was billed as an “emergency demonstration” in Parliament Square.

Activists demanded “trans liberation” and “trans rights now,” with some waving flags and holding banners.

Trans groups are worried that Wednesday’s landmark decision would undermine their rights, even though the U.K.’s highest court said transgender people remain protected from discrimination. The head of Equality and Human Rights Commission said the ruling will mean transgender women will be excluded from women’s toilets, hospital wards and sports teams.

The British government has said the unanimous decision by the five judges brought “clarity and confidence” for women and service providers.

Out of some 66 million people in England, Scotland and Wales, about 116,000 identified as trans in the latest census count. About 8,500 gender recognition certificates have been issued.

The ruling stemmed from a 2018 law passed by the Scottish Parliament that required at least 50% women on boards of Scottish public bodies. Transgender women with gender recognition certificates were to be included in meeting the quota.

The Supreme Court said that using a certificate to interpret someone’s sex would clash with definitions of man and woman and, therefore, the anti-discrimination provisions of the 2010 Equality Act could “only be interpreted as referring to biological sex.”

Scotland’s First Minister John Swinney said Saturday that he “understands” the “hurt and anguish” trans people are feeling over the verdict, while accepting that the ruling must be followed.