The Russian alliance, which came at the time when Ferry's policy was justified in the eyes of the public, too late for him to enjoy any credit, gave a new impetus to the French idea of establishing an empire in the Far East. In the opinion of all the prophets of Europe the great international struggle in the near future was to be that of England with Russia for the possession of India. If Russia won, France might have a share in the dismembered Indian empire, of which part of the frontier now marched with that of French Indo-China, since Burma had become British and Tongking French. Such aspirations were not formulated in white-books or in parliamentary speeches. Indeed, the apprehension of difficulty with England limited French ambition on the Siamese frontier. That did not prevent dangerous friction arising between England and France on the question of the Mekong, the river which flows from China almost due south into the China Sea traversing the whole length of French Indo-China, and forming part of the eastern boundary of Upper Burma and Siam. The aim of France was to secure the whole of the left bank of the Mekong, the highway of commerce from southern China. The opposition of Siam to this delimitation was believed by the French to be inspired by England, the supremacy of France on the Mekong river being prejudicial to British commerce with China. The inevitable rivalry between the two powers reached an acute crisis in 1893, the British ambassador in Paris being Lord Dufferin, who well understood the question, upper Burma having been annexed to India under his viceroyalty in 1885. The matter was not settled until 1894, when not only was the French claim to the left bank of the Mekong allowed, but the neutrality of a 25-kilometre zone on the Siamese bank was conceded as open to French trade. It is said that at one moment in July 1893 England and France were more nearly at war than at any other international crisis under the Third Republic, not excluding that of Fashoda, though the acute tension between the governments was unknown to the public.