An Irishman has been arrested in southern Portugal in possession of 12,000 doses of cocaine and 3,000 of heroin, the Portuguese police announced yesterday. The 30-year-old man, suspected of being a major drug trafficker, was arrested along with a Portuguese national in Albufeira, where police said he had been living. They did not give his identity. Both men are accused of forming part of an international drug smuggling ring.