The British media are thick with speculation as to what made young people run riot, set fire to buildings, ransack shops and run through the streets with their booty in full view of others.

Was it really because a man was shot by police? Was there any similarity between what happened in London and Manchester last week and what happened in Los Angeles in 1992 after the ‘Rodney King’ jury acquittal?

It’s because they’re disengaged from society, some commentators said. It’s because they are recent immigrants and haven’t integrated, others said, ignoring the glaring evidence that most of the rioters were white and many of those who were not had the kind of awful accents that suggest they were British born and bred.

Perhaps if they had more money, the lefties said. Perhaps if they had more education and were given more attention, The Guardian whined. If we send in the army, fire the rubber bullets and bring out the water-cannon, we lose the moral high ground, the BBC said, pointing out that Britain has no recent tradition of using force to quell riots, except in Northern Ireland.

Allowing Britain to keep its grand tradition of not sending in the army and the water-cannon came at a very high price, and that price was paid mainly by private citizens, who were left to stand helpless and unaided as they saw their buildings burned to the ground and their business premises ransacked and burgled in broad daylight.

A wave of irritation washed over me as I read and listened to these weak and ineffectual attempts to find an explanation for all this anti-social behaviour. It was as though media pundits and those whose advice they sought were struggling hard to seek a reason for – and thereby excuse – behaviour they found otherwise inexplicable in terms of 21st-century civilisation.

Can people raised in an urban environment really be mere savages beneath the veneer of fashionable (but chavvy) clothing and expensive sports shoes? Yes, they can. The trouble with those well-meaning leftie liberal media pundits is that they seek to measure everyone else by their own yardstick.

I’m a bit of a leftie liberal myself, but when confronted with this sort of thing I morph into a Telegraph reader or Margaret Thatcher, and think that what they need is a good whipping, a couple of blasts from a water-cannon and a long spell in the cooler. And I also know that it won’t make a blind bit of difference, because what we are dealing with here is a class of person who can best and most accurately be defined as a savage living in the compound of civilisation.

True savages know no morality. They are not immoral, because to be immoral one must be aware of the dictates of morality. They are amoral. They do not have any sense of right or wrong, but know only what is against the law and what is not. Though they know that stealing is a crime, they have only a vague sense of why this might be. The only thing stopping them from committing crimes is the fear of getting caught and sometimes not even that. Sometimes, the only thing that stops them is the size of the fine and the length of the prison term. If they can get off with a caution, they’ll go right ahead and do it. The reasoning is “It’s worth it, so why not”.

So it is obvious that when an opportunity comes along for wholesale looting, burgling, arson and ransacking, without fear of getting caught because the crowds are too great and the police are out of their depth, the thousands of people who think this way will get stuck right in and take advantage of the situation. As one young looter interviewed by the BBC in Manchester put it: “Why pass up the chance to get expensive stuff for free?”

The interviewer asked him if he stole the shoes he was carrying because he couldn’t afford to buy them. “I can afford to pay for them,” the looter said, “but why bother if I can get them for free? Nothing’s going to happen to me for doing it. I might get yelled at when I get home, but if I get caught, it’s just a first offence and I’ll be let off with a caution.”

I’m translating freely here, because his accent was so dreadful that his spoken words needed subtitles, though of course there were none. The BBC only provides subtitles for the spoken words of foreigners, like Germans, who are speaking heavily-accented English, even though they are far more intelligible than those of Manchester slum-dwellers.

There you have it, in a nutshell. They do it because they can, and no need for any extensive sociological theories. Instead of comparing their behaviour to the riots caused by food and poverty in other centuries, we should more accurately compare it to the looting and ransacking perpetrated by invaders and corsairs in centuries earlier still.

Attempts were made by some commentators to blame it all on the video game Grand Theft Auto, which is all about crime in an amoral landscape. But Grand Theft Auto (my sons played it regularly and they weren’t out looting and rioting with the best of them in London) has nothing to do with it. It describes a mindset and is not its cause.

Long before there was Grand Theft Auto, video games or even televisions, there were people like the Manchester looters and rioters. Some of them were responsible for the depopulation of outlying villages in Malta and Gozo before the 19th century. Others wiped out whole indigenous populations in the Americas. And many of those looting and rioting in Manchester and perhaps even in London are doubtless descended from Scandinavians who burned, looted and murdered their way into the British hinterland in the 10th and 11th centuries.

When law and order collapse, however temporarily, with human beings it’s back to basics. This is a popular theme in fiction and films only because it’s so true.