Prisons, after all, are social institutions grounded in the sex binary: that one is either male or female. Transgender prisoners challenge such a binary.

The current Prison Rules state that male and female prisoners should be kept separate from each other. This is not a British idiosyncrasy.

The United Nations Standard Minimum Rules for the Treatment of Prisoners state that 'Men and women shall so far as possible be detained in separate institutions; in an institution which receives both men and women, the whole of the premises allocated to women shall be entirely separate'.

It does not need spelling out why keeping male and female prisoners in separate accommodation should be one of the minimum expectations for the treatment of prisoners. This important principle has, though, been somewhat eroded by attempts to accommodate those prisoners who assert a gender identity at odds with their birth sex.

The current Prison Service Instruction on transgender prisoners highlights a legal judgement from 2009 that stated that a male-bodied prisoner who had a gender recognition certificate as a female 'had to be transferred to the female estate even though one of her index offences was attempted rape of a woman'.

This judgement forms the basis of the current prison service approach. The Instruction also gives senior managers discretion to transfer prisoners who do not have a gender recognition certificate to the estate of their asserted gender identity.

It concerns me greatly that we appear to have reached a position where male-bodied prisoners can gain transfer to a women's prison on the basis of assertions about their gender identity. While some transgender prisoners will no doubt sincerely hold beliefs about their gender identity, the system is obviously open to abuse.

So what is to be done?

First, it is reasonable for those who express a gender identity at odds with their birth sex to expect that their feelings will be respected.

I myself do not feel in a position to pronounce on whether or not 'transwomen are women', as the current mantra would put it. As a man, I also feel uncomfortable about telling women what a woman is.

But it is not necessary to take a position on this question to acknowledge that, for whatever reason – and these will be numerous – certain people have beliefs about their gender that differ from their birth sex.

Second, it is important that prisoners who express a gender identity at odds with their birth sex are held in safe conditions while in prison.

Third, women's prisons should be women-only spaces. By this, I mean we should reaffirm, in line with national and international standards, that they are institutions that hold, exclusively, girls and women whose birth sex is female.

There are numerous reasons why this should be the case. Highly vulnerable, often traumatised, prisoners are the rule, not the exception, in women's prisons. Many have faced male sexual violence and exploitation.

Consider what it must be like for women who have experienced male violence to have males imprisoned alongside them.

There are other concerns too. The Chief Executive of the Howard League, Frances Crook, told last weekend's Sunday Times that she had 'personally witnessed female prisoners visibly "intimidated" by a male-bodied trans inmate in their midst. "The trans prisoner was dominating the space and the women were round the edges," she said.'

While male prisoners asserting a female gender identity should not be sent to women's prisons, the Prison Service needs to give serious thought to transgender wings or other facilities where they can live out their identity in a more comfortable environment than is likely to be the case in a conventional male prison.

When it comes to the proper management of prisons, it is important that the welfare and safety needs of all prisoners are taken into account.

My concern about the current approach is that it is appears to privilege the subjective feelings of particular, largely male, prisoners, at the expense of the needs of those prisoners, largely women, who have to live with the decisions imposed upon them.

Not unreasonably, many feel that the needs and interests of female prisoners are being ignored or devalued.

The question of how to manage the particular challenges of transgender prisoners is emotive. Strong feelings, sometimes badly expressed, are much in evidence.

If we are to find a workable, and fair, solution, it is going to require calm, considered and respectful discussion.

An shorter version of this article is also available on Twitter.