The Gurkha tradition of foreign military service stretches back to the Anglo-Nepalese War of 1814-1816, when the British were so impressed by their opponents that they began recruiting them into the British Indian Army. When the Indian subcontinent gained independence in 1947, a tripartite agreement between Britain, India, and Nepal divided the Gurkha regiments: six went to the Indian Army, four to the British Army. Those transferred to Britain served across the empire's remaining outposts, from Malaya during the Emergency to Hong Kong and Singapore. It was from these far-flung postings that Brunei drew its recruits. The sultanate formally established the Gurkha Reserve Unit in 1974, building it from former Royal Gurkha Rifles troops through an extensive recruiting campaign launched in 1976. Unlike their counterparts in the British Army, these Gurkhas answered directly to the Sultan of Brunei.

The comparison to Rome's Praetorian Guard is not accidental; military analysts have used the term to describe the unit's role. Approximately 2,000 Gurkha soldiers serve in Brunei, tasked with protecting the royal family, the citizenry, and the country's major oil installations. The unit falls under the Ministry of Home Affairs rather than the military proper, and its commandant is personally selected by the Sultan. Every member holds the legal powers of a police officer and is classified as a government employee under Brunei's Penal Code. They are well-paid and well-housed, a standing professional force in a country with a population of roughly 450,000. Prior to Brunei's independence in 1984, their deployment was governed by a confidential agreement between Brunei and Whitehall, and the battalion remained in the sultanate at Brunei's expense under that arrangement.

The relationship between the Gurkhas and their employer has not always been smooth. At one point, more than 2,400 of the approximately 2,500 Gurkha soldiers in Brunei organized, forming a governing committee and subcommittees to press their grievances. They submitted a written memorandum requesting better treatment, including an end to what they described as maltreatment by officers and a demand for higher pay. One of their most dramatic requests was the abolishment of the GRU itself. The memorandum was rejected. In a remarkable act of collective defiance, the Gurkhas returned all their weapons to the Brunei government in a single night. The standoff resolved quietly: the unit resumed its security role, and the episode faded from public memory, a footnote that the Nepali Times later described as a forgotten Gurkha rebellion.

Today the Gurkha Security Unit, as it has been renamed, comprises three main branches: the Guard Unit, the Support Unit, and a K-9 Section. The K-9 program expanded in 2019, when Dog Force Australia provided a Train the Trainer Course to six seasoned handlers, focusing on explosive detection, search, and patrol duties. The unit rotates personnel from its headquarters, with members historically moving through postings at Seria, home to Brunei's oil fields. Recruitment remains bound by strict terms: no member may serve past age 40 without the Minister's consent and the Commandant's recommendation. Service contracts define the relationship from start to finish. For the young Nepali men who make this journey, the posting represents something complicated: a well-compensated career far from home, defending another nation's wealth, carrying forward a tradition that began when their ancestors faced the British and earned their respect through combat rather than surrender.