Earlier in the year, the government ordered a review of the law around knife crime in response to concerns raised by the Youth Justice Independent Advisory Group. Today, they've come up with their policy package - an assortment of preventative measures, and raising the sentence for posession of an offensive weapon from two to three years. The latter sounds like a knee-jerk, until you realise that it brings it into line with the penalty for posession of burglary instruments; it seems the law was placing a higher value on the property rights than people's lives.
OTOH, there's no real evidence that higher sentences deter. Currently, there are over three thousand investigations a year for this offence (and a further thousand for the summary offence of carrying a knife in a public place). And I don't think the headline sentence increase will make any difference at all to that number. Quite apart from the fact that criminals don't do a rational cost-benefit analysis weighing the risks and rewards of whether to break the law, there are basically two reasons why people carry weapons: because they want to hurt someone, or because they are afraid of being hurt themselves. And in either case, that reason outweighs any concerns about possible sentences.
So basically, while the preventative measures might help, the headline change is pointless spin, an attempt to make it look like the government is doing something which will in fact make no difference whatsoever. What's scary is that this is about the best we can expect from this government on law and order issues. It could have been much worse - they could have left it in the hands of Judith Collins...