Italian police arrested more than 300 people Thursday in the biggest operation against the mafia since a crackdown on Sicily’s Cosa Nostra 30 years ago.

Night-time raids were conducted by 2,500 paramilitary police officers, some of them equipped with night-vision goggles, as well as soldiers from the army’s parachute regiment and elite helicopter-borne tactical units.

The coordinated raids targeted the feared ‘Ndrangheta mafia from Calabria, the southern region that forms the toe of the Italian boot.

Police said they had dismantled a sophisticated criminal web that linked mafiosi with politicians, lawyers, accountants and Freemasons.

In one of the properties that was raided they found a scrap of paper with details of the secret blood oath that new members of the ‘Ndrangheta must swear, replete with esoteric references to swords and white horses.

Among the 334 people arrested was a former MP in Silvio Berlusconi’s party and a colonel in the police force, as well as the head of the association of mayors in Calabria. They were charged with crimes ranging from murder and extortion to loan sharking, money laundering and mafia association.

Many of the raids were conducted against ‘Ndrangheta clans in and around the town of Vibo Valentia but there were also arrests in other parts of Italy, from Tuscany and Veneto to Piedmont and Lombardy, northern regions where the ‘Ndrangheta buys up businesses to launder its criminal earnings.

Arrests were also made in Switzerland, Bulgaria and Germany. Police seized more than 20 weapons, including rifles and sidearms.

Property and assets worth 15 million euros were confiscated, in what Luciana Lamorgese, the interior minister, described as “a heavy blow” to the ‘Ndrangheta.

“It’s the biggest operation since the Palermo maxi trial,” said chief prosecutor Nicola Gratteri, referring to a trial involving 475 members of Cosa Nostra that was held inside a bunker in Ucciardone prison in Palermo. The trial lasted from 1986 to 1992.

The operation, which was based on years of intelligence-gathering and covert surveillance, was initially scheduled for today (Friday), but some of the suspects got wind of it, said Mr Gratteri, a renowned anti-mafia prosecutor.

“We had to bring it forward by 24 hours, which was a big problem,” he said. Some of the suspects had links to Masonic lodges in England and Scotland, he said. They had “betrayed” Masonry, the prosecutor said. “We should be careful not to speak generically about Masonry – being a Mason is not a crime.”

But those arrested had used their Masonic links to further the ‘Ndrangheta’s business interests, he said, without giving further details of the British lodges.

The arrested politician was Giancarlo Pittelli, a former senator with Forza Italia, the centre-Right party led by Mr Berlusconi, who was prime minister of Italy three times. Pittelli was also a former member of the justice commission in the lower house of parliament.