Businessmen in Sicily who have risked their lives by taking a stand against extortion rackets vowed to “fight to the end” yesterday after the Mafia hit back by attacking a key campaign headquarters and stealing documents.

Computer disks containing confidential details of businessmen backing a campaign against the payment of protection money, or “pizzo”, were stolen before arsonists burnt local offices of the employers’ federation.

Since August dozens of extortionists named by businessmen have been given heavy sentences after unusually swift trials, and ordered to repay protection money with interest.

Ivan Lo Bello, the head of Confindustria – the Italian CBI – in Sicily, said that the raid on the organisation’s offices in Caltanissetta was done to intimidate businessmen prepared to join the “anti-pizzo” drive. “But it won’t work,” he said. “Far from being intimidated we will redouble our efforts.”

Ettore Artioli, a businessman in Palermo, who rpresents Confindustria in southern Italy, said that the raid was the latest in a series of warnings to make them give up. “It is a sign that the Mafia is in serious trouble.”

Three weeks ago anti-Mafia police in Palermo arrested Salvatore Lo Piccolo, the Mafia godfather, and his son, Sandro. Mr Artioli said: “When I first heard about the Caltanissetta attack I felt demoralised. I thought, our struggle is hopeless. But then I thought of all the headlines about us, and the arrest of Lo Piccolo, and I thought no, we go forward.”

Since the anti-pizzo campaign began in August the businessmen leading it – mostly men in their forties with a global outlook and experience outside Sicily – have had their premises burnt down and their families threatened. In classic Mafia death warnings, severed heads of rabbits or goats have been left on their doorsteps and bullets have been sent to them. Several, including Mr Montante, Marco Venturi, head of the small businesses’ association in Caltanissetta, and Mr Lo Bello, have been given police protection. Mr Montante, who runs an engineering company whose customers include Virgin Trains, said that “some local businessmen and politicans are still colluding with Cosa Nostra. There is a white collar Mafia.” Mr Lo Bello said that there were “some businessmen who would prefer things to remain as they are and are trying to slow us down, but they too are making a big mistake”.

Clemente Mastella, the Justice Minister, said the businessmen had his full support, but Giuseppe Barcellona, the Chief of Police at Caltanissetta, said that the authorities needed more resources to fight the Mafia.

Businesses pay an estimated €30 billion (£20 billion) a year in extortion money in Sicily, southern Italy and, increasingly, in areas of northern Italy infiltrated by the Mafia. According to police estimates, pizzo costs an average €500-600 a month for shopkeepers, hotels and restaurants, with factories and construction companies paying thousands of euros a month.

Mr Mastella called on Canale 5, a television channel owned by Silvio Berlusconi, the former prime minister, to dropIl Capo dei Capi (The Boss of Bosses), a drama about Totò Riina, the godfather captured in 1993, because it risked glamorising Cosa Nostra. Pietro Valsecchi, the producer, said that Mr Mastella could not have seen the series because it is about the victims.

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