Mr Davis (not to be confused with their other David Davis, the shadow Home Secretary) showed a depressing lack of insight into the criminal justice system.

He began with the astonishing statement

"The reality is that prison works, and it is high time that we all recognised that."

Reading West MP Martin Salter asked if he could explain why, if that was the case, 70 per cent of young men leaving prison reoffended within two years.

To howls of laughter from both sides, Mr Davis replied

" I am delighted to do so: it is because they are not put in prison for long enough." 

He tried to justify this by comparing the reoffending rate for people sentenced to more that ten years (30 per cent) with the rate for those sentenced for under 12 months (70 per cent). But of course he isn't comparing like with like. The kind of offences that attract sentences of ten years or more include murder, manslaughter and GBH. They tend to be committed under great stress in the heat of the moment, typically in fights or domestic disputes. By their nature they have low reoffending rates.

Offences attracting a year or less are often associated with drug addiction, poverty and homelessness, none of which are cured by a spell in prison.  

Now, Mr Davis may well be a twit, because even he admits that he is unlikely to ever be a minister "... under any Government, Conservative or Labour." but it is worth emphasising that there is absolutely no evidence from any country that increasing the sentence for an offence leads to reduced offending or reoffending rates.

To suggest anything else is just plain wrong.