Soon after the declaration of war on Japan, a secret military reconnaissance unit was established, based on the British Special Operations Executive (known as SOE) and called the Inter-allied Services Department. The unit was tasked with the role to 'obtain and report information of the enemy ... weaken the enemy by sabotage and destruction of morale and to lend aid and assistance to local efforts to the same end in enemy occupied territories.' In 1943 it became known under the cover name Special Reconnaissance Department (SRD) and included some British officers who had escaped from Singapore. After arriving in Australia, they assembled in Melbourne, forming the nucleus of ISD and together with some Australians established what became the Z Special Unit. During the course of the war, Z Special Unit carried out 81 covert operations in the Southwest Pacific theatre. While the unit was disbanded after the end of the war, many of its techniques would be modified and used by Australian Special Forces to this day.