Fao Richard Burgon, Alan Travis and Frances Crook

If people want to argue that privately run prisons are wrong, fine - but let them argue the case, and not merely assert it.

But too often, they assume that because they personally think the idea wrong in theory, it must be wrong in practice too - privately run prisons must fail, because they think they should. And here they part company with reality. And that I do not respect.

Among such ideologues are: Richard Burgon, Labour Justice spokesman; Alan Travis, the Guardian Home Affairs correspondent; and Frances Crook, chief executive of the Howard  League (for over 30 years! - come on, trustees, wakey wakey!).

My book shows that over 25 years, neither sector has convincingly and consistently done better than the other, though quite clearly, the private sector has been cheaper. And since all public spending has an opportunity cost, that you might think that means the private sector has done better.

Here is the assessment of the (public sector) HM Prison and Probation Service Agency for prisons in 2017-18, based on an elaborate methology which includes asking prisoners what they think, via anonymised surveys.

 Of course, where ideology collides with reality, ideology usually wins.  So I am not expecting to change any minds. Or even open them. 

But let the facts speak for themselves.