The gang also looked into expanding its business to Cuba with the aim of installing solar panels to provide energy to the Cuban government in exchange for minerals.

During phone-calls with Cuban officials, gang members claimed to have close links to Spanish political leaders.

Each of the raided properties in Madrid, Málaga, Marbella, Torremolinos, Coín, Ayamonte and Lisbon contained a high-security safe and a money-counting machine stored in a sound-proof cabinet used to obscure the recognisable noise of the money counters.

Gang members avoided detection by regularly changing location and vehicles and using encrypted mobile phones.

The phones were linked in such a way that should a member of the group be arrested, the mobile phones of the entire ring would be simultaneously locked down.

Police say the three ringleaders remain in custody and say other arrests are possible.