Any kind of violence is disturbing, of course. But it seems more so when the perpetrators are female, and young as well. Some might think that's a very sexist thing to say. Well, maybe it is. But then human nature is pretty sexist.

Men -- particularly young men with their bodies full of testosterone -- are naturally very aggressive. Throw in other factors such as emotional scars caused by parental or other abuse, lack of good role models, poverty, allegiance to a gang, drugs and alcohol and you have an explosive mix. That's why so much violence is committed by young males. That's not to say that it's acceptable. It's just an unfortunate fact of life.

Females just aren't as hormonally souped up! So if they're acting like wayward, damaged young males it shows that society has fractured to an even greater extent.

That's definitely happening in Perth. This report, for example, describes recent attacks committed by one or more girl gangs.

This reminds me of an experience I had in Forrest Chase a couple of months ago. I was in the Subway there, and a group of Aboriginal teenage girls walked past. They were in high spirits and wanted to make mischief, so one of them leaned in and grabbed a plastic bottle of spray-on cleaner that was sitting on top of the bin near the door.

The staff didn't see this but I did, so I stood up and told her to put it back. She did so, but then dared another, older girl to take it. This girl looked at me, then grabbed the bottle and walked out with it. The other girls thought this was hilarious. I got up and followed the girl out saying: "You can't do that. Give it back." She backed away, laughing, and even pressed the nozzle, spraying the vapour in my direction. The rest of the gang were very impressed.

A few seconds later I gave up the chase because I realized I couldn't retrieve the bottle without making physical contact with the girl. If I'd done that I'm sure they would have wasted no time in accusing me of assault, and loudly. So I let them get away with it.

I went back and told the Subway staff what had occurred. They just shrugged. Things like this had obviously happened many times before.

The girls didn't act violently but their brazen disregard for the law was quite amazing. They stole property in broad daylight in the middle of the CBD and got away with it.

I found this very depressing. But the thing that made it even more so was the fact that they all seemed comparatively happy, healthy and well dressed. There are some young Aborigines whose deprivation is obvious. Their clothes are dirty or torn, they aren't wearing shoes, their hair is matted, and they are clearly under the influence of drugs. But these girls were not like that at all.

Obviously what's occurring here in Perth is nowhere near as bad as what happened during the London riots. But I can't help thinking that David Cameron's subsequent description of parts of British society as "broken" is also somewhat valid here.