Over thirty years ago when we still had Mental Hospitals, someone told me it was hard to get admitted to one if you were seriously mad. Seriously mad people created a lot of work and stress. They couldn't be relied on to do as they were told. It's true that they could be zonked with sedatives but, on balance, leaving them to roam the streets seemed better policy. There they were someone else's problem.
I am sure this is a caricature of a tendency but it has coloured the way I think about the Police and what are now called "Historic Crimes". The police like dealing with historic offences because they are manageable. You can work on them 9 to 5 in the comfort of your office, you don't have to show results quickly - after all, these cases have been around for decades already - and if they involve well known persons, victims or perpetrators, then there are stories to be passed on to the press.
On balance, then, to ensure that valuable (and expensive ) police time isn't wasted, I would impose a Statute of Limitations on all but the most serious crimes. After one or five or ten years, criminal investigations would not be revived except in cases of murder, GBH which had left someone disabled or otherwise affected, sexual offences involving violence or coercion, violence (whether or not sexual) against children. For the moment, I stop there. The objective is not to deny that past crimes were crimes, even quite serious ones; simply to ensure that the police have time - and use it - to chase today's criminals even when that involves a lot of hard work and stress.
It may also be a reasonable objective to encourage all of us to think of misfortunes - even those which are legally crimes against us - as things which, in time, we should simply file away and forget about.
I have never been the victim of a crime that has marked me for a long time afterwards so maybe I am being smug. I have occasionally been the victim of small crimes which I would not want investigated or investigated again. Here's one by way of thought experiment.
Over thirty years ago, my car - a Sunbeam Rapier with which I was rather chuffed - was stolen from outside my flat in Castle Crescent, Reading. I reported the theft to the police, I am sure, because otherwise I would not have known to go down into a city centre underground car park where the car had been taken and stripped of its wheels. As I recall, its location in an area where there were low concrete beams above meant that it could not be lifted out for removal. It had to be dragged out, damaged in the process and written off.
Now if the Police suddenly contacted me to say that they now knew who committed this 1977 crime (maybe someone loudly recalling old times over a drink in a pub), I would say Thank You but immediately go on to say that I had no desire for them to do anything about it. I would not want anyone prosecuted even if that did not involve me in going to Court. If it did involve me in going to Court, I most definitely would not want anything done. The loss of my Sunbeam Rapier is a historic crime in two senses: it took place over thirty years ago and I have no need to recall it other than as an anecdote. Nor can I see any reason to take someone to Court for it: I have no reason to want the person (s) who took my car then punished now. Even the idea seems faintly ridiculous. It was all so long ago and the car thieves have also lived their lives since then, maybe blamelessly maybe not - it doesn't much matter.
I realise I have chosen a piddling example to illustrate my case.But once the general principle is granted, that some crimes should simply be forgotten for police and judicial purposes, then it becomes possible to ask questions about Which crimes? and How Long?