Right of Passage Case (Portugal v India) (Custom between two nations)

In 1785, Portugal, which already had colonial territory in India, purchased the district of Dadra, which then became a Portuguese possession and remained so for more than 150 years. During the decolonization era, which followed the Second World War, Great Britain gave up its colonial possessions in India and India emerged as an independent state. Portugal, however, maintained its various colonial possessions, including Dadra. Dadra was landlocked and did not border any other Portuguese territory, so the only way to access it was through Indian territory. During the colonial era, Great Britain had always allowed Portuguese access to Dadra, without exception, other than in relation to armed troops. It's hardly surprising that Great Britain did not want armed personnel from another country moving through its territory without permission. In 1954, as part of the broader effort to end colonial rule in India, certain Indian factions stormed into Dadra. They found it essentially undefended. The total Portuguese force consisted of three police officers. The Indian groups immediately took effective control of the district. Portugal moved to exercise its sovereignty by defending its colonial possession, but India shut down access to the enclave by road. No reinforcements could realistically be provided. Portugal did not concede the loss of its territory and the following year, in 1955, commenced an action in the International Court of Justice, demanding access by road to its territory. The court found that there was a right of access, which had its basis in the customs which had long been observed between the two countries, but the court found that the right of access did not extend to moving military personnel into the enclave. The court said, With regard to private persons, civil officials and goods in general, there existed during the British and post-British periods a constant and uniform practice allowing free passage between Daman and the enclaves. This practice continued over a period extending beyond a century and a quarter. However, during the British and post-British periods, Portuguese armed forces and armed police did not pass between Daman and the enclaves as of right, and that, after 1878, such passage could only take place with previous authorization by the British and later by India. In consequence, Dadra was left essentially undefended and remained under Indian occupation until 1974, when a treaty between Portugal and India gave the territory over to be part of India.