Stories are emerging of Londoners forming vigilante groups to protect their homes and businesses, but police have warned this is making matters worse.
When rioters struck in Stoke Newington, north-east London, on Monday night, a group of Turkish shopkeepers were in no doubt about what was required.
Arming themselves with rudimentary weapons - a rubber hose or a piece of metal from a hoover - they were poorly equipped to see off the hundreds of youths who were running amok, smashing windows and setting fire to homes.
But their statement of intent was clear.
"Every man is entitled to defend his castle and we'll defend the shop against anybody," said one.
In the aftermath of the initial rioting in Tottenham four nights ago, traders and residents have accused the police of standing by and allowing people to loot.
Others spoke of how powerless they felt watching family businesses or homes burned to the ground.
But little by little a picture is emerging of Londoners beginning to fight back against the wave of violence - in some cases by taking the law into their own hands.
In Southall, west London, hundreds of Sikh men stood guard outside their temple and patrolled the streets on Tuesday night.
"We want to show the rioters we are here together," the temple's president, Himmat Singh Sohi, told Sky News.
Reports have suggested that some people protected their homes armed with just pots and pans, while others formed lines outside to stop looters breaking in.
But when is it right to take the law into your own hands?
No-one can forget the case of Tony Martin, the Norfolk farmer who shot and killed Fred Barras, 16, after he broke into Martin's home.
Martin was jailed for murder, and the case provoked a debate that has not gone away.
Criminologist Roger Graef says that, as a society, we endorse self-defence - and the right to protect property was endorsed very recently by the prime minister himself.
"We will put beyond doubt that homeowners and small shopkeepers who use reasonable force to defend themselves or their properties will not be prosecuted," said David Cameron in June.
His pledge was put to the test a few days later when a Salford homeowner stabbed to death a man who was trying to break in to his house. The homeowner was not prosecuted.
But, says Mr Graef, there is a subtle but important difference between protecting your own home and actively chasing after those who have threatened you.
"The move from self-defence to vigilantism is almost a matter of point of view," he says.
"The difference is whether you have gone out after the person who has attacked you.
"Self-defence has been endorsed very recently, even by the prime minister, but vigilantism is when you go out after the person who has threatened you - and that is not tolerated."
He is not surprised people have turned to their own means to protect communities.
"It's not unexpected in the circumstances," he says.
"They have experienced the police standing by while looting is going on. It was only a matter of time."
Help or hindrance?
The national press is making its own attempts to bring the rioters to justice: the Sun urges readers to "Shop a moron".
And a peaceful fight-back is under way on the streets of London as post-riot clean-ups organised on Twitter and Facebook make an impact.
But for others the fight-back involves a much more direct approach.
In Enfield on Tuesday night, a group of men dressed in white T-shirts were out on the streets.
Boiler technician Dean Nelson, 33, explained: "We're not going to stand here and take it any more.
"The 350-400 people in Enfield town tonight show that it's about time we stood up - not for violence but just to stand here and show we're not going to take it any more."
Another, named only as Steve, warned: "Get the water cannons out, rubber bullets, whatever they [the police] need to do to protect us. If they don't, this is what's going to happen."
Cliff Knight, a resident of New Addington, close to Croydon, said: "People just don't want to have what's happened in main Croydon happening in our community. We protect our own homes - we don't want that up here."
But are those who take the law into their own hands to protect shops and homes more of a hindrance than a help?
Clive Efford, MP for Eltham, is among those who think they can be.
"A group of the English Defence League turned up in the high street and have been drinking all day, and although they say they're here to assist the police, they [the police] have now diverted all these resources here," he told BBC Radio 4's Today programme.
Scotland Yard sounded a similar warning.
"What I don't need is these so-called vigilantes, who appeared to have been drinking too much and taking policing resources away from what they should have been doing - which is preventing the looting," said Met Police Deputy Assistant Commissioner Steve Kavanagh.
He added: "These are small pockets of people. They're frustrated, they're angry, and that's totally understandable.
"The sadness of those images through the night and the night before last will affect everyone, but the support that we need is to allow those officers to prevent looting and prevent crime."
He urged people not to take the law into their own hands.
So can turning vigilante ever be right?
"I can't say very simply they [vigilantes] shouldn't do it because if somebody was attacking my home I would want to protect it," says Mr Graef.
It is a dilemma every shopkeeper and homeowner in rioted-afflicted areas will be battling, he says.
"It's a massive problem for the police but it's also a massive problem for householders and shop-owners.
"The idea of them getting involved against an out-of-control crowd of youths who are much stronger and more agile and determined to cause damage - it's quite brave people who will take on an attack like that."