According to figures released by the Ministry of Justice, one in five Muslim prisoners in England and Wales are now white, compared with around 6% of Muslims as a whole. At first glance, that number may look relatively benign: men finding faith and perhaps a sense of purpose behind bars. But the truth is much darker.

During my 16 years in prison, I saw Islamist groups offer frightened and susceptible prisoners protection, status and belonging — sometimes backed by intimidation — in exchange for conversion. And as the number of Muslim people in British prisons grows, accounting for nearly a fifth of all prisoners, vulnerable people on hostile wings increasingly find themselves joining strong groups not as a theological decision but rather as a survival strategy.

That is not to say that all conversion is dangerous. I saw Islam give men genuine discipline and purpose. But the scale of the disparity between the number of white Muslims in prison and the rate within the general population makes it important to understand how this has happened.

Prison strips people of much of what previously defined them. Family disappears, status changes and a person becomes an inmate with a number and an offence attached to them. Many arrive frightened, isolated, resentful or simply searching for a different way to live. A strong religious community can fill that void remarkably quickly.

I watched new arrivals being welcomed into Islamic groups, offered food and friendship and gradually introduced to a new set of values. For some, that was spiritual, but for many others it offered protection. For those searching for influence, affiliation with a powerful group could provide that too.

And prisons merely intensify changes occurring outside them. As changing demographics in Britain lead to heightened tensions between different ethnic, cultural and religious groups, those divides are only increased in the closed and high-pressure environments of prisons — places already shaped by trauma, mental ill-health, addiction and violence.

But why is the dangerous end of conversion so hard to stop? Partly because the boundary between legitimate faith and extremist recruitment is extremely difficult to police. Two Muslim prisoners discussing the Quran in a cell may simply be exercising their religion. Another conversation could involve a committed Islamist teaching a new convert that Western values are the enemy. But an officer cannot simply interrupt every religious exchange to assess its intent.

Such uncertainty is also compounded by institutional timidity. Staff know that intervention can produce complaints of racism or Islamophobia. Ian Acheson’s 2016 review found that cultural sensitivity was inhibiting “the effective confrontation of extremist views” among Muslim prisoners. Add overcrowding, inexperienced officers and weakened authority on the landings, and the space available for informal prisoner power grows.

We already know where this can lead. Baz Hockton entered prison as a violent offender, converted to Islam in custody and was subsequently radicalised. In 2020, alongside convicted terrorist Brusthom Ziamani, he attempted to murder a prison officer at HMP Whitemoor while wearing a fake suicide belt.

That is an extreme case, but it shows why intent matters. The Prison Service must understand what surrounds conversion: who provides the belonging, who supplies the ideas and what happens to a prisoner afterwards. If they fail to do so, some prisoners will leave with more than a new faith — perhaps a new enemy.