This is the article that Heather mentioned:
"But one governor, speaking on condition of anonymity, said: ‘My fear is that this could make it much harder to control the transfer of born-male, transgender prisoners to women’s prisons.
‘This could lead to vulnerable women being intimidated – and even attacked.’
The warning came as the Ministry of Justice confirmed that dozens of ‘trans-identified male’ prisoners are living as women in jails exclusively housing convicted sex offenders."
additionally...
"Prison reformer Frances Crook said that she was worried that ‘some men with a history of extreme violence and sexual violence against women have found a new way of exercising aggression towards women’
Ms Crook, executive director of the Howard League for Penal Reform, added: ‘These men are not transitioning because they like women and want to be a woman, but in order to exert a new kind of control and dominance over women, a sort of infiltration.
‘Moreover, the process is inherently discriminatory. A woman identifying as a man could not be transferred to a man’s jail because placing a person with female attributes into a prison to live with 1,000 men, all using communal showers and living areas, would put them in serious danger.’"
www.dailymail.co.uk/news/article-5798945/Trans-women-convicted-men-attack-vulnerable-inmates.html