The Accord provided that Tibet would be divided into “Outer Tibet” and “Inner Tibet”. Outer Tibet, which roughly corresponded to Ü-Tsang and western Kham would “remain in the hands of the Tibetan Government at Lhasa under Chinese suzerainty”, but China would not interfere in its administration. “Inner Tibet”, roughly equivalent to Amdo and eastern Kham, would be under the jurisdiction of the Chinese government. The Accord with its annexes also defined the boundary between Tibet and China proper and between Tibet and British India (the latter became known as the McMahon Line).However, China rejected the Accord and their plenipotentiary, Ivan Chen, withdrew on 3 July 1914. The British and Tibetan plenipotentiaries then attached a note denying China any privileges under the Accord and sealed it as a bilateral agreement the same day:
We, the Plenipotentiaries of Great Britain and Tibet, hereby record the following declaration to the effect that we acknowledge the annexed convention as initialed to be binding on the Governments of Great Britain and Tibet, and we agree that so long as the Government of China withholds signature to the aforesaid convention she will be debarred from the enjoyment of all privileges accruing therefrom.
Communist China has argued that because it did not sign the Simla Accord, it did not surrender its claim to Tibet. This argument misses the point. The results of the Simla Conference are not principally what demonstrates Tibet’s capacity to enter into international relations. Rather, it is the participation of Tibet as an equal party which demonstrates that capacity. Because Tibet participated as an equal with China and Great Britain, Tibet and Great Britain could only have entered a treaty if Tibet were an autonomous state, albeit one with links to China. A binding treaty could have resulted from the Simla Conference, had the negotiations gone well, because the parties had the capacity to form such a treaty.
McMahon’s work was initially rejected by the British government as incompatible with the 1907 Anglo-Russian Convention, but this convention was renounced in 1921. Consequently, the British began using the McMahon Line on Survey of India maps in 1937, and the Simla Accord was published officially in 1938. Prior to 1937, Burma was a province of British India. It is noteworthy that, when China and Burma settled their border in 1960, they defined it along the McMahon Line.