The blood ties have created powerful groups with links to emigre communities in Australia, Canada and Germany, and cities in the north of Italy, through which they launder drug money. These family relationships make the 'Ndrangheta almost impenetrable to investigators, since it's extremely difficult to persuade a collaborator to betray his own brothers.
In the mid-90s, in Calabria, there were 27 "penitent" mafiosi, while in Sicily there were more than 400.
Because of these ties, every power struggle between Calabrian clans is termed faida, summoning the image of a folkloric ritual. Vendettas or honour killings do still occur, claiming the principle of a "just murder".
Two years ago a man was shot dead for dating a woman while her boyfriend, a member of the San Luca clan, was in prison. As in all mafia incidents, no crime can go unanswered, and the victim's family quickly avenged the killing. The blood feud has also led to an image of local savagery, perpetuated by the discovery in 1992 of young mafiosi in Gioia Tauro using a human head for target practice.
However, magistrates in Calabria sounded the alarm a few years ago about the international scale of the 'Ndrangheta's operations. It is now believed to have surpassed the traditional axis between the Sicilian and American Cosa Nostra, to become the major importer of cocaine to Europe.
The global scale of the 'Ndrangheta's operation puts the "blood feuds" in a different light: the San Luca family is battling not merely for the honour of its members, but for a major role in the cocaine traffic between Colombia and Germany.
The 'Ndrangheta has periodically created alliances with the Sicilian Cosa Nostra to infiltrate local government and fix major building and transport contracts. The most notable of these joint projects is the bridge across the Strait of Messina. Bernardo Provenzano, boss of Cosa Nostra until his arrest last year, was heard to gloat: "If they build that bridge there'll be enough money for everyone."
· Clare Longrigg is the author of Mafia Women (Vintage)