Transgender women are still being held in women's prisons despite a Supreme Court ruling that sexes must be segregated.

A group of five transgender prisoners are being held in HMP Downview in Surrey, sparking fresh concerns that they pose a potential risk to other inmates.

Activists have said the wing is not effectively separated from the rest of the building, and are calling on Justice Secretary David Lammy to bar transgender prisoners from being held there.

They argue this year's Supreme Court ruling that segregation between men and women should be on the basis of biological sex rather than their chosen gender identity.

A spokesman for Labour Women’s Declaration, which campaigns for sex-based rights, said: "Vulnerable female prisoners must be prioritised.

"Housing male offenders, regardless of how they identify, in the female estate violates the rights and safety of women prisoners and breaches the Supreme Court ruling.

"It has now been five months since it was clarified that sex in the Equality Act 2010 refers to biological sex.

"If he chooses to act decisively, Secretary of State for Justice David Lammy has an important opportunity to both ensure the safety of women in custody and reaffirm Labour’s commitment to defending women’s rights. We trust he will make the right choice."

The five prisoners are being kept at HMP Downview, a female prison in Sutton, Surrey