The population of Britain's only dedicated wing for transgender prisoners has increased despite the Supreme Court ruling on biological sex. 

Seven inmates with male genitalia were serving time on E wing at HMP Downview in February, according to a new inspection - up from five in November last year. 

The unit is reserved for trans women with a history of sexual or violent offending who are in possession of a gender recognition certificate stating their gender as female. 

But its future has been thrown into doubt after the Supreme Court ruling that - for the purposes of the Equality Act - the definition of a woman must be based on biology.

This means single-sex spaces, such as prisons or domestic abuse refuges, must exclude biologically male transgender women.

Rebecca Paul, the MP whose constituency covers Downview in Surrey, has called for the ruling to be 'implemented in full and at all levels'.

Set up after trans prisoner Karen White sexually assaulted two female inmates at HMP New Hall in West Yorkshire, E wing is intended to separate potentially dangerous offenders from women inmates, many of whom are victims of sexual abuse.

Prisoners from E wing are allowed to mix with women prisoners for activities and workshops, but the MoJ insists this only happens after a 'rigorous local risk assessment' confirms this is safe. 

A new report by Charlie Taylor, HM Chief Inspector of Prisons, found these risk assessments were 'robust'. 

However, he noted that E wing officers had to be regularly reminded about the restrictions in place for each prisoner. 

The wing became Europe's first 'jail within a jail' for male-born trans inmates in 2019.

The latest inspection by Downview's Independent Monitoring Board (IMB) in October described it as 'toxic' and 'full of drama', with inmates spending their days slumped in front of the television rather than working or attending classes. 

According to the IMB, many refused to take part in work or education, instead spending hours in the recreation room 'watching daytime television'.

Inspectors wrote: 'At various times, the atmosphere on the wing was challenging...with frequent conflict, bullying, exclusion and flashpoints in prisoner relationships.

'It was often described by prisoners and staff as 'toxic' and 'full of drama'.'

One prisoner admitted she rarely left her room because of 'the drama on the other side'.

The wing was opened after the 320 female prisoners at Downview reported 'significant concern' at the arrival of trans inmates, almost half of whom were sex offenders.

At the time, prison governors and doctors warned sex criminals were transitioning to get access to women.

Sex predator Karen White, a biological male who identified as a woman, sexually assaulted women at HMP New Hall prison while on remand for rape in 2018.

In his own report, Mr Taylor said the future of the wing remained unclear. 

'The Government's failure to respond to the April 2025 Supreme Court ruling left prison leaders in a difficult position, creating ongoing uncertainty about the future of the E wing unit for transgender prisoners,' he wrote.

Campaigners have urged ministers to shut the unit down immediately, saying the trans inmates may still pose a risk to female prisoners.

A spokesman for Labour Women's Declaration previously 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.'

The spokesman added that Justice Secretary David Lammy had an 'important opportunity' to show that Labour was serious about protecting women's rights. 

A Ministry of Justice spokesman said: 'There is a separate unit for transgender prisoners at HMP Downview isolated from the main female population.

'The vast majority of transgender women in prison are in men's prisons, and we are reviewing our transgender prisoner policy in light of the Supreme Court ruling.'