Secret Intelligence Australia

Secret Intelligence Australia (SIA) was a British World War II intelligence unit commanded by Captain Roy Kendall, operating under MI6 in London and not accountable to Australian or American authorities. It functioned as Section B of the Allied Intelligence Bureau and specialized in gathering enemy intelligence through secret methods, particularly targeting the Netherlands East Indies (NEI) via Islamic channels.

SIA’s operations initially focused on introducing native religious leaders, such as Hajjis from Mecca, to counter Japanese propaganda and maintain Islamic solidarity. Despite challenges in infiltrating NEI and northern Australian islands, SIA later succeeded in obtaining valuable intelligence before Allied forces occupied areas like Halmahera. The unit also established a Celebes coastwatcher network under the "Co-monitor" plan, operating in the Banda Sea and relaying signals to control stations in Biak and Darwin.

In 1945, near the war’s end, SIA set up five secret stations in Java for intelligence and weather reporting. These included stations near Soerabaja, the Sunda Straits, and three on islands around Java, which remained operational after hostilities ceased to monitor Japanese renegades.

SIA operatives were trained at locations like Caboolture, Queensland, and the Z Experimental Station in Cairns. The unit’s headquarters was located at "Craigroyston" in Brisbane. Known operations included CAEN, BATH, LONDON, CREW, DOVER, and LEEDS.