An international drugs and money laundering syndicate has been smashed by a joint European and Australian police operation following the world's largest single seizure of ecstasy with a street value of $A440 million (£204.5million).

After a 12-month investigation into the syndicate, whose tentacles reached from The Netherlands to India and Australia, police across Western Europe and Australia began making arrests in the early hours of today. In Melbourne, Australia, the Australian Federal Police (AFP) arrested 16 of the syndicate's leaders. Similar raids were being carried out throughout Europe.

The investigation was triggered by the discovery of 15 million pills - 4.4 tonnes - of ecstasy, or MDMA in Melbourne in June last year. The drugs had been imported from Italy, and were hidden inside more than 3000 tomato tins stored in a shipping container.

A joint operation between the AFP and the Australian Customs Services resulted in the drugs being substituted with a harmless substance. The tins were then monitored for a year, eventually leading police to members of the syndicate, who include an alleged drugs baron, members of the Calabrian mafia, well-known figures of Australia's underworld and an outlaw motorcycle gang.

The operation also led Australian customs officers to 150kg of cocaine hidden inside another shipping container which arrived in Melbourne last month, and the exposure of a money laundering operation worth more than £4.1million which the gang used to buy the drugs, police said.

AFP Commissioner Mick Keelty hailed the arrests as a “major victory” in the fight against international drug syndicates.

“This is an extraordinary outcome for law enforcement as it continues to work together to detect illicit drugs before they reach Australia,” he said.

Mr Keelty said raids had also been conducted in Belgium, the Netherlands and Italy, while German police were also involved in a specially formed European police taskforce. Raids in Europe were still underway, with £394,000 (€500,000) worth of drugs seized.

Five people were also arrested in relation to the case by Indian police in Mumbai on December 17 last year.

"International intelligence, combined with the cooperation of local law enforcement agencies, played a big role in the success of the operation," Mr Keelty said.

He said the operation, which involved more than 400 Australian police, had been the largest in his force's 30-year history.

Mr Keelty said police were surprised that the syndicate was involved in such a big operation that they did not seem bothered to have lost the initial 4.4million tonnes of ecstasy and instead continued to import more drugs.

Mr Keelty named one of those arrested as Pasquale “Pat” Barbaro, 46, whose family was once named in a judicial inquiry into the 1977 disappearance of a prominent Australian anti-drugs campaigner.

Mr Barbaro’s property in Griffith, a regional town in NSW, was also raided. Griffith was named by a Royal Commission as home to a cell of the Calbarian mafia.

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