Russia had already penetrated all the sphere allotted to it and was rapidly expanding into the regions beyond. Its political influence at Tehran was proverbial. The commercial value of the British zone was not its main attraction in 1907, although it was known to be a region of oil fields, the full richness of which became apparent only subsequently. Many Englishmen, although recognizing their inferior influence in Iran at the time, criticized the convention, particularly its clauses on Iran.
Lord Curzon, for example, launched a full-dress attack upon it in the House of Lords. After calling it “the most far-reaching and the most important treaty which had been concluded by the British government during the past fifty years,” he charged that “we had thrown away the efforts of our diplomacy and our trade for more than a century, and had handed over to Russia not only the trade route from Baghdad but also the important marts of Isfahan and Yazd.”
The convention was favorably received in Russia. The Russian Duma welcomed Izvolsky's speech and his mention of the convention amid applause and shouts of “bravo.” M Judging from what had been demanded by some “Russian imperialists” during the course of negotiations, it may be safely assumed that even in Russia the convention met with some criticism, although by no means so severe as in Great Britain and western Europe. “Russian imperialists” had demanded that Iran come entirely under Russian influence and that Russia build a trans-Iranian railway and press on to the Persian Gulf.” Both British and Russian critics argued for a larger share for their respective countries rather than against the partition of Iran.