The 1907 Anglo-Russian Treaty, which had earlier caused the British to question the validity of Simla, had been renounced by the Russians in 1917 and by the Russians and British jointly in 1921.
Den 1907-anglo-russiske traktat, som tidligere havde fået briterne til at stille spørgsmålstegn ved Simlas gyldighed, var blevet opsagt af russerne i 1917 og af russerne og briterne i fællesskab i 1921.