Children are always trying to define boundaries – they invariably need to see how far they can go before sanctions follow. We have all seen harassed parents threatening a misbehaving child, but rarely do we see the oft-threatened sanction materialise. The

Children are always trying to define boundaries - they invariably need to see how far they can go before sanctions follow. We have all seen harassed parents threatening a misbehaving child, but rarely do we see the oft-threatened sanction materialise.

The child eventually learns that the phrase "if you do that once more, I will not buy you any sweets" is meaningless. Provided that he or she apologises and looks suitably sorry at the checkout, the sweets will materialise.

Many parents feel they have an excuse for not instilling much discipline, or any sense of moral values, in their children. When both parents have to work to make ends meet, they only want to have a meal and relax when they get home, not demonstrate their parenting skills.

There is a tendency to feel the education system ought to do that, with the police waiting to enforce the wilder outrages. Such parents feel no moral duty to contribute towards either process.

However, teachers in schools are no longer allowed to exercise the sort of discipline my generation was subject to. I know there will be arguments about how reasonable that discipline was, but through my entire grammar school phase (during which I would doubt if teachers saw me as particularly well behaved) it was only necessary to apply "six of the best" twice to my rear end. That averaged less than once every three years but, for the remainder of the time, the knowledge that it just might happen again kept me in the general vicinity of the straight and narrow.

The police, too, have a difficulty fulfilling their side of the bargain that the above-mentioned parents believe in. They tell us that they do not have enough resources to deal with speeding in villages, parking on double yellow lines, or using a hand-held mobile phone while driving.

Everyone knows they have quite a reasonable chance of getting away without sanctions being applied if they do those things. The people that get away with it are now parents and their children get to see how little advertised boundaries seem to mean.

I find it difficult to shout at children for riding cycles on the wrong side of the road, at night and without lights. I still do it, but I know in many cases they are merely aping what they have seen their parents do.

So, why am I banging on about this like the reactionary old wotsit that I am? Well, I think it has a bearing on the current frightening growth in knife crime. The considerable number of young children now carrying knives do not believe that a serious sanction might follow - any more than do the considerable proportion of drivers who overtake me with a mobile phone clamped to their ear. Until the probability of a sanction is seen as a significant risk, we will not see a serious change in behaviour in either case.

The Government's immediate knee-jerk reaction is to announce that some new legislation may be enacted at some indeterminate time in the future.

Why not try (just as an experiment, of course - I should not like them to change the habits of a lifetime just for me) actually enforcing the legislation that already exists? Only 14 per cent of the people convicted of carrying a knife are actually imprisoned. So why argue about whether the maximum term should be two years (as at present) or five years?

When cases come to court, how can we dispel the prevalent idea that dressing up in a suit, looking penitent, and claiming to have learned a lesson will somehow make the sanctions available in law disappear? If any of our JPs had heard the offenders laughing with their friends immediately afterwards, they might just feel they had been taken for a ride. Can't they see that the magistrate's bench and the supermarket checkout mentioned in the first paragraph above, are very similar? And that magistrates and harassed parents have a lot in common?