Amid headlines about the threats, Prime Minister Silvio Berlusconi and other public figures last week declared solidarity with Saviano and urged him to stay in Italy. The extent of the peril is not clear because the supposed tipster has retracted.

But anti-mafia officials have little doubt that Saviano remains in danger.

The title of the book alludes to the biblical city of sin, Gomorrah, cited in a denunciation of the mob by a crusading priest who was assassinated in 1994.

Despite his impassioned hatred for the gangsters, Saviano acknowledges that the success of Gomorrah and TV series such as The Sopranos shows that the underworld exerts a persistent hold on the popular imagination.

“In the book I deal with that fascination, because they have it. But I dismantle it. I explain the tricks they use to appear fascinating, the way they dress and so on... But in reality, it is a life of s—-. They are always shut inside their homes. They have the same women who they have to share because they do not trust anyone, so it’s not true that they are big playboys.”

Whatever the future holds, Saviano takes comfort from the courageous example of figures such as prosecutor Falcone and Salman Rushdie, the British author who has lived under a death threat issued by Iran’s fundamentalist regime in 1989.

“He told me, ‘Liberate yourself, because no one else is going to liberate you’.”