Mafia bosses do not come much more brutal than Giuseppe and Filippo Graviano. Among the crimes, for which the brothers have been serving life sentences since 1994 are involvement in the murder of two anti-Mafia judges, the killing of an anti-Mafia priest, the bombing of the Uffizi Gallery in Florence and another in Rome that killed 10 people and injured 93.

Yet both have shown an unexpected aptitude for turning their brainpower to a higher purpose: academic study. They recently gained first-class degrees — Giuseppe in mathematics and Filippo in economics.

Prison authorities said that a growing number of imprisoned Mafia killers are taking degrees, and that their motives may not be entirely to do with academic achievement.

“A favourite subject is law,” Giuseppe Giustolisi, an expert on the Mafia, said. “Either they want to find out where they went wrong, or they hope they will get out one day and that detailed knowledge of the law will help them to evade prison in future.”

He said that another motive was that they were allowed to travel to the university where they had enrolled to take exams — and the universities were often in their home towns.

“I am worried that this loophole in the high-security system enables them to somehow communicate with their local henchman,” Sebastiano Ardita, the former head of the Italian prison service, said.

Mafia bosses with first-class degrees include Pietro Aglieri — convicted for killing the judges Giovanni Falcone and Paolo Borsellino — who graduated in theology. Aglieri was a lieutenant of Totò Riina, who was arrested after the murders of Falcone and Borsellino in 1992, and Bernardo Provenzano, who was arrested near Corleone in Sicily.

Neither Riina nor Provenzano are known for their interest in reading, apart from the Bible, which Provenzano used as a codebook for cryptic messages to subordinates. Aglieri was known in the Cosa Nostra as 'U Signurinu (the Little Gentleman) for his love of the Greek and Latin classics.

Other mafiosi with degrees include Antonio Libri, convicted of extortion and kidnapping in Reggio Calabria, who studied sociology, and Giuseppe Gullotti, convicted for murdering a journalist, who studied law.

Mr Ardita said: “I do not believe they have changed their ways. There is something more to it.” He said that a display of intellectual superiority helped Mafia bosses to maintain their “supremacy” over clans, and travelling to their home turfs to take exams offered “a loophole in a system that is supposed to isolate them”. Antonio Ingroia, an anti-Mafia prosecutor in Sicily, said: “It does seem absurd to relax a high-security regime intended to ensure they have no contact with the criminal underworld.”

However, Emilio Santoro, a professor at Florence University, said that even Mafia bosses deserved a chance to better themselves. He cited the case of Carmelo Musumeci, a mafioso from Catania, who gained a law degree with a dissertation on “the experiences of prisoners serving life sentences”.

Mafia prisoners are held under a security regime known as 41b, which the European Court of Human Rights in Strasbourg has criticised as excessively harsh. They are allowed only two visits a month and open-air exercise for up to four hours a day.

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