It is essential for those in power in Britain that the riots now sweeping the country can have no cause beyond feral wickedness. This is nothing but "criminality, pure and simple", David Cameron declared after cutting short his holiday in Tuscany. The London mayor and fellow former Bullingdon Club member Boris Johnson, heckled by hostile Londoners in Clapham Junction, warned that rioters must stop hearing "economic and sociological justifications" (though who was offering them he never explained) for what they were doing.

When his predecessor Ken Livingstone linked the riots to the impact of public spending cuts, it was almost as if he'd torched a building himself. The Daily Mail thundered that blaming cuts was "immoral and cynical", echoed by a string of armchair riot control enthusiasts. There was nothing to explain, they've insisted, and the only response should be plastic bullets, water cannon and troops on the streets.

We'll hear a lot more of that when parliament meets – and it's not hard to see why. If these riots have no social or political causes, then clearly no one in authority can be held responsible. What's more, with many people terrified by the mayhem and angry at the failure of the police to halt its spread, it offers the government a chance to get back on the front foot and regain its seriously damaged credibility as a force for social order.

But it's also a nonsensical position. If this week's eruption is an expression of pure criminality and has nothing to do with police harassment or youth unemployment or rampant inequality or deepening economic crisis, why is it happening now and not a decade ago? The criminal classes, as the Victorians branded those at the margins of society, are always with us, after all. And if it has no connection with Britain's savage social divide and ghettoes of deprivation, why did it kick off in Haringey and not Henley?

To accuse those who make those obvious links of being apologists or "making excuses" for attacks on firefighters or robbing small shopkeepers is equally fatuous. To refuse to recognise the causes of the unrest is to make it more likely to recur – and ministers themselves certainly won't be making that mistake behind closed doors if they care about their own political futures.

It was the same when riots erupted in London and Liverpool 30 years ago, also triggered by confrontation between the police and black community, when another Conservative government was driving through cuts during a recession. The people of Brixton and Toxteth were denounced as criminals and thugs, but within weeks Michael Heseltine was writing a private memo to the cabinet, beginning with "it took a riot", and setting out the urgent necessity to take action over urban deprivation.

This time, the multi-ethnic unrest has spread far further and faster. It's been less politicised and there's been far more looting, to the point where in many areas grabbing "free stuff" has been the main action. But there's no mystery as to where the upheaval came from. It was triggered by the police killing a young black man in a country where black people are 26 times more likely to be stopped and searched by police than their white counterparts. The riot that exploded in Tottenham in response at the weekend took place in an area with the highest unemployment in London, whose youth clubs have been closed to meet a 75% cut in its youth services budget.

It then erupted across what is now by some measures the most unequal city in the developed world, where the wealth of the richest 10% has risen to 273 times that of the poorest, drawing in young people who have had their educational maintenance allowance axed just as official youth unemployment has reached a record high and university places are being cut back under the weight of a tripling of tuition fees.

Now the unrest has gone nationwide. But it's not as if rioting was unexpected when the government embarked on its reckless programme to shrink the state. Last autumn the Police Superintendents' Association warned of the dangers of slashing police numbers at a time when they were likely to be needed to deal with "social tensions" or "widespread disorder". Less than a fortnight ago, Tottenham youths told the Guardian they expected a riot.

Politicians and media talking heads counter that none of that has anything to do with sociopathic teenagers smashing shop windows to walk off with plasma TVs and trainers. But where exactly did the rioters get the idea that there is no higher value than acquiring individual wealth, or that branded goods are the route to identity and self-respect?

While bankers have publicly looted the country's wealth and got away with it, it's not hard to see why those who are locked out of the gravy train might think they were entitled to help themselves to a mobile phone. Some of the rioters make the connection explicitly. "The politicians say that we loot and rob, they are the original gangsters," one told a reporter. Another explained to the BBC: "We're showing the rich people we can do what we want."

Most have no stake in a society which has shut them out or an economic model which has now run into the sand. It's already become clear that divided Britain is in no state to absorb the austerity now being administered because three decades of neoliberal capitalism have already shattered so many social bonds of work and community.

What we're now seeing across the cities of England is the reflection of a society run on greed – and a poisonous failure of politics and social solidarity. There is now a danger that rioting might feed into ethnic conflict. Meanwhile, the latest phase of the economic crisis lurching back and forth between the United States and Europe risks tipping austerity Britain into slump or prolonged stagnation. We're starting to see the devastating costs of refusing to change course.