It has emerged that it costs 63% more to keep a criminal in prison in Northern Ireland than it does in England and Wales.
The figures (£57,000 a year per prisoner here, £22,000 a year more than there) have been issued to Jim Wells MLA, after a written Assembly question from him.
The cost has come down, Claire Sugden, the justice minister, explained. It remains higher per prisoner for reasons such as segregation and economies of scale that are not possible in a place as small as Northern Ireland.
To a large extent, that might be so.
But it is important that this higher cost does not lead, as it easily could, to a reduced reliance on prison as a penalty for serious crime.
Already Northern Ireland has alarmingly light sentences, for a range of offences including – recently – grave terrorist acts and serious instances of death by dangerous driving (most famously the disgracefully inadequate sentence given to David Lee Stewart, who under the influence of drugs and alcohol knocked down and killed the student Enda Dolan).
Nor should it lead to any compromise in the protection of our brave Prison Service staff, whose lives are at risk from the dissident republican terrorists that they have to control.
There is no shortage of groups clamouring on behalf of such prisoners, and citing ‘human rights’ findings about jail conditions in a bid to make prison life easier for those who murder, maim or try to do so.
We must never lose sight of the right to life of those whom the terrorists target. Long periods behind bars is what these thugs must receive.
We need a comprehensive study of why prison places are so expensive in Northern Ireland. Might it be, for example, that an increase in the number of such places will lead to economies of scale and a lower cost per prisoner?
If that frees up space for longer sentences, it will be a good thing.