The military aggression of alied Forces against Iran during the Second World War escalated a momentous campaign Which led to the victory of Iranian National Movement. A decade of ceaseless concerted efforts made it tremendously popular with the people hence highly successful. This Movement had all the potential elements to achieve it,s goals with regards to holding free elections and enforcement of the law of nationalisation of oil industry. however the iranian nation were subject to british conspirecy to stamp out national Iranian Movement. The British Government engaged with a direct interference in internal affairs of Iran by her domestic Pawns to destroy this Movement. Notwithstanding, the claim concerning the so called "Coup", There were no action from military units of army aginst mossadegh,s governement. Violation of Separation of Powers, getting the full authority from parliament through intimidation of MPS, weakening and the dissolving of the Parliament, to give a free hand to the commusist party in the political arina, to lead to bankruptcy the national economy through creating a deadlock in oil issue, intentionally leaving the people in the dark concerning the unfolding events, were the real causes of defeat of national movement of Iran