I find the bare facts of this quite astonishing - and there is no clear or simple explanation. From the 2011 census, of a population for England and Wales of 56.1m, some 2.7m declared the Muslim faith - about 4.8% (Source: ONS). However, latest government figures give the Muslim prison population across England and Wales at 14% - rising to 27% in London prisons, with 29% in Belmarsh - almost a third of all those held there.
With the current prison population in England and Wales of about 83,000, that's nearly 12,000 Muslims locked up across the country, at a cost of £38,000 a year each - some £442m annually in total. If Muslims were imprisoned at a rate consistent with their share of the population, only 3,980 of them would be banged up - saving nearly £300m a year. The costs of the crimes and offences that put them there are of course incalculable; as are the costs of the police and security services in tracking and monitoring those connected with terrorism.
There is surely more to this than an increased proclivity to criminality. It may be that the population of young Muslim men at peak offending age is higher than other population cohorts, or there are particular problems with for example drugs or sexual offences amongst Muslims. Whatever, we need to understand exactly why this is happening.
And of greatest concern, as prison is often a hothouse for radicalising previously non-extremist Muslims, we will also have created a very considerable number of potentially asocial, criminally inclined extremist jihadists all due for release.
I've found a 2010 Justice Department report on this subject HERE; this suggests that up to 30% of Muslims in prison are converts, and up to 19% of them are Afro-Caribbean. However, the numbers - both absolute and proportionally - have grown since this report, which indicates this may be a growing problem.