Image showing a cue sport competition, with a focus on a female player holding a cue stick during an 8-ball pool match. Represents the Ultimate Pool Women’s Pro Series amid recent policy changes affecting transgender participation.

Transgender women have been barred from competing in the female category of Ultimate Pool Group (UPG) events, following a landmark ruling by the UK Supreme Court which clarified that the legal definition of "woman" is based on biological sex.

UPG, the professional body overseeing 8-ball pool, announced an update to its eligibility policy, stating that participation in the women’s division will now be "open only to biologically born women."

The decision comes in the wake of protests earlier this month at the final of the Ultimate Pool Women’s Pro Series Event, where the finalists Harriet Haynes and Lucy Smith are both transgender women.

In a statement, UPG said that "recent developments have now made the position clear," and welcomed the "clarity" provided by the Supreme Court’s decision.

A commissioned report also concluded that 8-ball pool is a “gender-affected sport,” noting that female players face unique disadvantages when compared to male players and that transgender women may retain physical advantages.

UPG emphasized that its open category will "remain available to all, regardless of sex."

“We understand that some in the pool community may find these changes difficult,” the organization stated. “As an inclusive body, we remain committed to showing empathy and respect to all members of our community, and we expect everyone involved to uphold these values.”