The most important rule in the favelas, though, the one that overrides all other concerns and is most viciously enforced, is this: you are not allowed to do anything that might be construed as threatening or in any way impinging upon the traffic of drugs. In some favelas, you cannot call an ambulance, and no garbage whatsoever can be collected, because the police might use those vehicles as Trojan horses. Beyond that, new rules can be declared at any time according to the whims of the boss. They might be something like these, again from Melo's Inferno: "Anybody who talks to a reporter dies. Anybody who talks to the cops dies. Anyone who does anything stupid after ten at night dies. The next one to die is the preacher."

Some bosses are better than others, but to those living in the favelas, all police are more or less the same. "They only come in here to kill," says Natalia. A Human Rights Watch report released last December reveals that the Rio police kill roughly three times as many people every year as do the combined police forces of the US, and more than twice as many as the combined police forces of South Africa. The kills-to-arrests and kills-to-police casualties ratios are also shockingly high. Civilian deaths, accidental or otherwise, and summary executions of bandidos, are routine. The prevailing notion in the police force, only now beginning to change, is that they are at war with the favelas. The standard tactic has been the ruinous one of invading the favela in force to kill or arrest the bosses, and then withdrawing completely. The strategic focus has been simply on scrambling to meet the escalating levels of firepower possessed by the traffickers. When the previous state administration came to power in 2003, the following statement of intent came not from some incarcerated drug kingpin, but from the Public Security Secretary, Anthony Garotinho: "Our movement is on the streets, and if there has to be armed conflict, there will be. If someone has to die as a result, let them die. We're going in hard."

The current state administration, however, under Governor Sérgio Cabral, sworn in at the beginning of 2007, has shown itself willing to adopt new ideas. "Cabral is very special," says José Junior, the executive director of the AfroReggae Cultural Group, one of the many NGOs that does excellent work in the favelas. "His family was always involved with urban questions, and he has already managed, with billions of reais, to improve conditions in many favelas, by investing in technology, establishing centres for emergencies and so on." Crucially, Cabral's party, the Party of the Democratic Movement of Brazil (PMDB), is allied with President Lula's Workers' Party ahead of the elections later this year. "For the first time in my life, there is genuine collaboration at state level with both the federal government and the private sector," says Junior. Policing strategy is also changing. In a New Yorker article in October, Jon Lee Anderson quoted City Councilor Alfredo Sirkis as describing the drug mafias as "a low-intensity, nonideological insurgency." What follows from this observation is a new scheme now being piloted in seven favelas in the city. The traffickers are eliminated by the usual aggressive means, but then a "Peacemaking Police Unit" (UPP) takes up a permanent presence in the community. More than 3,000 military policemen have been selected from the best young recruits, promised salary bonuses, and allocated to UPPs. José Mariano Beltrame, the current Public Security Secretary, estimates that 30 per cent of favela residents will be living under the protection of UPPs by the end of 2010. Combined with continuing investment and infrastructure building, and the continuing work of NGOs, this could be something approaching the "full-spectrum counterinsurgency" that the US military wants to implement in Afghanistan.

Most people I spoke to had heard good reports about UPPs in other favelas and were cautiously hopeful. Ana Caroline wants a UPP to come to Maré, which is one of the most dangerous favelas in Rio due to the presence there of all three mafias. They clash frequently at the borders of their territories, in an area of the complex known as "the Gaza Strip". "But only if it works, if it's not just cosmetics. Because what they show you on TV is one thing, and real life is another" she says. "In some ways, the history of Brazilian government is the history of putting make-up over a problem," explains Gabriela Pinheiro from Luta Pela Paz ("Fight For Peace"), an NGO that runs a boxing academy in Nova Hollanda and has an alumnus in Brazil's Olympic team. Fernando would like to see a UPP in Rocinha, but fears that because the favela is so enormous, any attempt to wrest it from the traffickers would result in a long and bloody war.

Even if the UPP scheme is more than just make-up, there are massive challenges ahead. When the police invade a favela, the top traffickers usually know about it ahead of time, and make themselves scarce along with the best weapons and the high-grade drugs. It's thought that as favelas are reclaimed and pressure is exerted on the drug trade, the bandidos will either start appearing on the streets in large numbers, carrying out robberies and attacks against the police force, or move to annex favela territories belonging to their rivals. In either case, the level of violence will go up. An element so far missing from the strategy is what General David Petraeus would call "reintegrating reconcilables". José Junior tells me: "A bandido doesn't cease to be a bandido just because the police are in his favela. The government must agree to some kind of amnesty, like the Colombian government did with the militias there."