Pockets of London went into lockdown Tuesday, with shops closing, a surge of 16,000 police officers taking to the streets and helicopters buzzing overhead as a stunned Britain began running the calculus of the worst civil disturbances to rock the nation in a generation.

With London jails filled to capacity and violence escalating in Manchester, Birmingham and other parts Britain, the government faced the challenge of maintaining law and order in a country where the sense of security had suddenly been shattered. After a glorious spring in which a royal wedding celebrated all things British, the riots piled on to a summer of discontent plagued by a phone-hacking scandal, painful austerity and stock market drops.

At the same time, the trail of destruction after three nights of mob rule in sectors of the capital and other British cities left the nation confronting an over-arching question: Why?

On a street corner in Hackney, site of some of the worst riots Monday, Sivaharan Kanbiah, a 39-year-old Sri Lankan immigrant, stood shell-shocked outside his ransacked convenience store as residents packed bags and fled in fear. “You work all your life, and in one night, they come and destroy it,” he said. “They did not just steal everything. They tore out the ceiling. They broke up the floor. They ripped out the shelves. I don’t understand such hate.”

He paused, turned to one side, silently gathering himself. He voice cracked as he continued: “I have a wife, two children and a mother to support. Now I have no way to do it. They took my life, and I can’t replace it. We’ll be turned out on the street. I want to know why. Why?”

There were no easy answers.

The rioting was triggered by the fatal police shooting last week of a black North London resident. But many observers say that incident alone could not explain the multiracial rampage of burning and looting across the sprawling capital.

Some voices saw a culprit in growing inequality, poor police relations with minorities and especially the Conservative-led government’s austerity drive that was robbing disenfranchised youths of educational subsidies and youth centers as the economy teetered on the verge of recession.

In London, a handful of looters who spoke out talked of a lack of respect for the young and the poor, raging against an increasingly affluent city that had left them behind. The violence, they said, fueled them with a sense of empowerment.

“This did not come from nowhere,” said Diane Abbott, an opposition Labor Party lawmaker from Hackney, where shops closed and public buildings were evacuated at midday. The neighborhood is not far from the Olympic Park being built for next year’s Games.

Abbott denounced the violence but said that the “public sector is the biggest employer in Hackney. Now you have kids wondering if their mum will have a job. It’s not all about race. But it is about rich and poor.”

Yet most of the austerity measures — which the government would now be challenged to complete — have yet to come into effect, leading some to question whether they truly played a role. And just as many voices blamed a weak police response and a breakdown of family values years in the making for giving rise to a class of directionless youths.

Youth culture

Whatever the reason, the riots have exposed a desperate youth culture buried inside British society, with people linked to one another as never before through text messaging and social networking sites.

In one BlackBerry message circulating around London on Monday, a rioter called others to arms in the famous shopping district of Oxford Circus: “Everyone run wild, all of London and others are invited! Pure terror and havoc & Free stuff. Just smash shop windows and cart out da stuff u want!”

The violence in Britain has differed from the kind of politically charged protests seen recently in Greece and Spain in response to hard economic times. In Britain, the rage has appeared blind, apolitical and profoundly selfish. Looters set alight a historic department store, a Sony distribution center and tiny, family-owned groceries. They have burned the bikes of poor residents and the cars of richer ones. One gang of masked thugs burst into a fashionable Notting Hill eatery to rob diners, clashing with restaurant workers wielding rolling pins. Others rioters simply fought one another.

Closed-circuit cameras captured a young man, seriously injured and semiconscious, struggling to his feet amid the chaos in East London on Monday night. A group of looters seemed to comfort him, before one of them casually opened the boy’s backpack and robbed him as he helplessly watched.

On Tuesday evening, a committee investigating the death of Mark Duggan, the 29-year-old shot by police Thursday in Tottenham, released information indicating that he never fired his gun. Some feared the news could incite more violence.

But on Tuesday night, London appeared relatively calm, though police were fighting new running battles with rioters in Manchester and Birmingham. In the East Midlands county of Nottinghamshire, police said a group of 30 to 40 rioters had firebombed a police station, though no one was injured. Parts of Liverpool were in lockdown after someone tried to drive a truck through a post office.

“This is serious stuff, and it is going to impact the government — it is not good for a government to be seen not to be in control of the country,” said Tony Travers, a political analyst with the London School of Economics. “But it’s hard to see this as something that’s just developed, since the current government came to power in May 2009. It’s the kind of disturbing criminality that seemed to be bubbling for years.”

Cameron’s response

Nevertheless, the riots present a challenge to the Conservative-led government embarking on historic budget cuts — and now facing the public’s wrath over the handling of the riots.

Prime Minister David Cameron, who had been on vacation in Italy until Monday night, cut short his trip to return to London. He called for an emergency session of Parliament for Thursday.

Effectively acknowledging that the embattled Metropolitan Police had been overwhelmed — images showed riot police standing by as youths looted and set buildings ablaze — Cameron said a force of 16,000 would take to the streets Tuesday, up from 6,000 Monday night. Scotland Yard officials said they would employ additional methods, possibly including rubber bullets.

But he did not appear to embrace calls by some to deploy the army or water cannons to restore order. And after more than 450 arrests, authorities said prisons in London were reaching capacity, leading the newly detained to be bussed to jails outside the capital.

Cameron’s deputy prime minister, Nick Clegg, was booed and catcalled during an appearance in Birmingham. Boris Johnson, London’s Conservative mayor who had cut short his trip to Australia as the riots intensified, was booed by some in the middle-class Clapham neighborhood where 20 police officers were unable to contain 200 looters Monday night.

Though facing new questions about social exclusion, Johnson and other Conservatives dismissed that the riots were anything other than the product of poor parenting, wanting morals and misdirected anger.

“We’ve got to reclaim our streets,” Johnson said, later adding, “It is time that we heard a little bit less about the sociological justifications for wanton criminality.”

Special correspondent Rebecca Omonira-Oyekanmi contributed to this report.