After the riots came the looting. Across London windows were smashed, and shops emptied. On Monday experts said social exclusion and the breakdown of law and order could have spurred looters to disregard social norms.

"Many of the people involved are likely to have been from low-income, high-unemployment estates, and many, if not most, do not have much of a legitimate future," said criminologist and youth culture expert Professor John Pitts.

Unlike most people, some of those looting had no stake in conformity, he said. "Those things that normally constrain people are not there. Much of this was opportunism but in the middle of it there is a social question to be asked about young people with nothing to lose."

On much of the footage of the widespread theft after the riots, looters can be seen brazenly taking the goods they want, some without taking the precaution of covering their face. In one video shot early on Sunday morning in Wood Green, people can be seen leaving H&M with a haul of goods, with others standing around JD Sports apparently waiting for their turn to take goods.

One north London resident, who wanted to be identified only as Tiel, described a conversation: "I heard two girls arguing about which store to steal from next. 'Let's go Boots?' 'No, Body Shop.' 'Hit Body Shop after it's dead [meaning empty].'" The girl came out of Boots "nonchalantly, as if she'd done her weekly shop at 4:30am", he added. He described others, holding up clothes to themselves in the broken windows of H&M. "They were just so blasé about what they were doing."

In Wood Green about 100 youths targeted shops, including electrical stores and clothes chains such as H&M. "I've got loads of G-Star," said one teenager, emerging from a clothes shop. Other teenagers were seen with suitcases filled with stolen goods, and in the early hours of Sunday residential front gardens were used to sort and swap them.

Evidence has also been emerging that looters are attempting to sell their stolen goods. In Tottenham, just off the high street, one 20-year-old, who refused to give his name, said he had heard looters trying to get the booty off their hands as soon as possible.

"I know some were on corners trying to sell laptops from Currys for 20 quid. What you going to do with it?" he said.

Looters found ways to justify their actions, Pitts added. "They feel they can rationalise it by targeting big corporations. There is a sense that the companies have lots of money, while they have very little." Combined with a lack of intervention from police and increasing lawlessness, the combination was explosive: " [Looters] quickly see that police cannot control the situation, which leads to a sort of adrenalin-fuelled euphoria – suddenly you are in control and there is nothing anyone can do."

A generation bred on a diet of excessive consumerism and bombarded by advertising had been unleashed, he added. "Where we used to be defined by what we did, now we are defined by what we buy. These big stores are in the business of tempting [the consumer] and then suddenly these people find they can just walk into the shop and have it all."

One eyewitness, who asked not to be named, said a police officer patrolling Brixton Road on Monday morning told him he thought 12-year-olds were looting.

Dr Paul Bagguley, a sociologist at the University of Leeds, said looting was a common feature of most riots but a mixture of practical reasons could have increased its extent. Rising unemployment was important not only as a catalyst of unrest, but because it meant more people were unoccupied on the streets leading to "biographical availability". "It's a straightforward argument, but powerful. Without jobs people are more likely to be hanging around the streets. Also there are simply more desirable, portable consumer goods to steal than ever before."

Looting was seen as a less risky activity than rioting: "Looting tends to involve a wider range of people – children, women, older people – because it does not involve physical violence. Riots enable people to lose their inhibitions, give them liberty to do things they wouldn't normally do."

Areeb Ullah, a Tottenham resident, said looters had disregarded the needs of the area and local people. And while large stores were targeted, some smaller shops had not escaped the looting. "The businesses around here were barely getting by anyway. A flower shop was set alight. What has that florist ever done? I saw a man in his shop just crying. This is only going to make Tottenham worse."