How many people go camping in the Westcountry without a penknife of some kind in the glove compartment of their car? Only the foolhardy, we imagine, since a handy knife – particularly one of those Swiss Army models – is as essential a piece of kit as a waterproof jacket and a hat if you are venturing into the great outdoors.
Yet the sobering truth is that every one of them is potentially committing a criminal offence. After the conviction this week of disabled caravanner Rodney Knowles for possession of an "offensive weapon", the risk of any one of those innocent campers being arrested, taken to court and given a fine and, much, much worse, a criminal record is alarmingly high.
How on earth has it come to this? How has an entire group of people; law-abiding, taxpayers and in many cases pillars of the community, become criminalised for doing nothing more sinister than possessing a useful tool that is no more dangerous than a screwdriver or the wheel brace found in everyone's wheel-changing set?
The answer, sadly, is the frightening explosion of knife crime in London and some other inner city areas which has led to the deaths of a number of young men, who have been stabbed in street fights. Making the possession of every knife "without lawful excuse" a criminal offence is not the answer, however. Arresting Mr Knowles, taking him to court, forcing him to hand over his Swiss Army Knife and making him pay £40 in costs won't prevent a single vicious attack with a knife in inner-city Britain.
As so often happens the forces of law and order, from the politicians right down to the bobby on the beat, have come up with the wrong response to a serious problem. Like the dangerous dogs act and the banning of an entire category of firearm in the wake of the Dunblane tragedy, the innocent suffer and the guilty continue to carry out their criminal activities.
Has gun crime fallen significantly since the measures introduced after the horror of Dunblane? Have dog attacks and the number of intimidating dogs on our streets gone down since those laws came in? In both cases the answer must be no. A crackdown on the gangs engaged in knife crime may have reduced stabbings in London, but that has nothing to do with the harassment of innocent country lovers who slip a penknife into their pocket before they go out for the day.
And that, surely, is the point. Blanket bans persecute the innocent and make life more difficult for the very people the police and the law-makers ought to be working to keep onside. Every time they take a man like Rodney Knowles to court for carrying penknife used to cut up fruit, they chip away at the faith the majority of law-abiding citizens have in the police and those who direct them.
And in recent years the traffic has been in one direction only. We are now more closely monitored by hidden cameras, more tightly regulated by anti-terrorist measures and more tightly policed than at any time in our history. Yet we don't feel safer as a result. Just put upon.