The case also challenges policy on a unit for transgender women at HMP Downview in Surrey

A female prisoner who was allegedly sexually assaulted in jail by a male-bodied transgender inmate has launched a High Court action for a judicial review of government policy.

She says the transgender woman, who is serving a sentence for rape of a female, groped her breasts in the prison toilets. Shortly after the assault, the victim was moved to a different prison only to find her assailant had also moved there and would be sharing accommodation.

She is challenging the lawfulness of the government decision to place trans-women prisoners convicted of sexual and violent offences against women in women’s prisons without, it is claimed, adequately protecting female prisoners.

Her application, lodged in the High Court by Birnberg Peirce, a civil rights law firm, on October