This was an Allied unrealised operation to rescue British and Australian prisoners of war being held in a Japanese camp near Sandakan in northern Borneo (16 January/late March 1944).
In the later part of 1944, the Allies began to receive reports that the Japanese were seriously mistreating the 2,350 prisoners being held in the Sandakan camp, and it was decided to attempt a rescue operation. By the end of the year the required intelligence was under way as the Services Reconnaissance Department gathered information, and by January 1945 the latest intelligence reports indicated the serious nature of the plight in which the prisoners now were: many were starving, and some had been executed.
Evacuation shipping, aircraft and paratroopers were organised, but the operation still awaited final intelligence from the Services Reconnaissance Department before a start date could be scheduled. Photographic reconnaissance imagery requested in October 1944 was still not available, and it was then discovered that no such imagery had been taken.
The advance party of seven men boarded the US submarine Tuna on 16 January 1944 and departed for Borneo, unfortunately still without the intelligence imagery. When the submarine approached reaching Bisa island, it was clear that the Japanese had complete control of the area and the party returned to Australia.
Soon after this, reports indicated that the Japanese were massacring prisoners, and this made it vital that 'Kingfisher II' be launched as speedily as possible. Thus the party set out one more on 24 February, again in Tuna. At 19.00 on 3 March, the submarine surfaced 10,000 yards (9145 m) off the mouth of the Tagahan river and the preliminary party left in a seven-man rubber boat, towing another behind it. The two craft made their way into the mouth of the river and followed it upstream for about 4,400 yards (4025 m) and then made camp. On 7 March the party established radio contact, and on 27 March a radio message called for the establishment of an airstrip, but without more labour this was thought to be impossible and 'Kingfish II' was brought to an end.
On 22 May a report stated that all the prisoners at Sandakan had been moved to Ranau, and Allied bombing of the Sandakan area then began on 27 May. In fact the report was misleading, and some of the prisoners were still at Sandakan Eight-Mile Camp.
All but six Australians, who managed to escape, of the prisoners died, many of them murdered, in one of the worst Japanese atrocities of the war.