The unprovoked Allied invasion of Iran during WWII and Reza Shah of Iran

Reza Shah Pahlavi - The Invasion of Iran (Persia) by The Allied Force
History tells you everything you need to know for dealing with the present - if you go back far enough find out how deep the roots go.
You could go back to 1813 and the Treaty of Gulistan, under which Persia was forced to concede territory to Russia. The treaty was put together by British diplomat Sir Gore Ouseley and is regarded as a humiliation in Iran. The myth - or reality - of the devious British was established. Britain was also instrumental in setting Iran's borders with India in the 1860s.
In August 1941, the Allied powers of Britain, United States, and the Soviet Union invaded and occupied Iran by a massive air, land, and naval assault. They justified this by alleging that the Reza Shah had refused to allow Iranian territory to be used to train, supply, and act as a transport corridor by the Allied forces. Reza Shad had declared neutrality and wished to stay out of the war.
The Allies did not accept this neutrality and invaded Iran without any respect for its sovereignty in order to ship arms to Russia for its war effort against Germany. Because of its importance in the allied victory, Iran was subsequently called "The Bridge of Victory" by Winston Churchill.
Stalin and Churchill in military uniform, Roosevelt in suit meet in Tehran after invasion of Iran, 1941
Upon occupation of Iran, the British forced the Reza Shah to abdicate in favor of his son, a 21 year old boy with no knowledge of politics or statesmanship. The British wanted this inexperienced young man as their puppet so they could continue to rape the countries enormous natural resources and benefit from its geopolitical importance.
During Reza Shah's sixteen years of leadership, major infrastructural developments took place in Iran, most often under his direct supervision. The British had often expressed their displeasure with the rate of growth and advancements in Iran as they feared this may hinder the British efforts to continue control of Iranian natural resources through the colonial political and economic control backed by their military.
Despite the British attempts to clamped down on Iranian national prosperity and unity, there were many large road and housing construction projects that were carried out during the reign of Reza Shah including the Trans-Iranian Railway which was built quit rapidly (considering the limited experience Iran had) and well as other projects of importance to economic prosperity such as building a modern education infrastructure and the establishment of University of Tehran. The number of modern industrial plants, increased nearly 20 folds under Reza Shah, the number of miles of highway increased from 1900 to 14,300.
Reza Shah is the tall man in the center
In addition to the modernization drive of the nation, Reza Shah was the leader during the time of the Women's Awakening (1936-1941) which sought the elimination of the Islamic veil from Iranian society. Modern Iranian women believed that the veil impaired their ability to enter society and contribute to the progress of the nation and be regarded as an equal by men. The unveiling issue and the Women's Awakening are linked to the Marriage Law of 1931 and the Second Congress of Eastern Women in Tehran in 1932.
See: Iran as a Twentieth Century Victim: 1900 Through the Aftermath of World War II
During the nineteenth century, Russia and Britain competed for power and influence in Central Asia, in what was known as the Great Game. Needless to say, it was neither great nor a game for those countries, such as Iran, which were treated like pawns on a chessboard by the two great powers. By the turn of the twentieth century, Russia had come to dominate the northern part of Iran while Britain dominated the south. The two powers formalized this division in the Anglo-Russian Convention of 1907, which segmented Iran into three parts—a Russian zone in the north, in which Russia was to have exclusive political and economic control; a British zone in the southeast, in which Britain had the sole right to exercise political and economic control; and a neutral “buffer” zone in the rest of the country, in which both the British and the Russians shared power.
The British watching these development remotely, expressed concern in the British parliament and suggested that Reza Shah's policies of modernization is against British interests and they would much prefer for Iran to remain as is so that the British empire would find it much easier to rule the region. Additionally, the British were deeply concerned that Iran's developments may entice other countries in the region to follow similar trends and try to build economic prosperity and growth for their people.
The British never hesitated to express their displeasure for Reza Shah and held intense views of resentment towards him.
As his reign became more secure, Reza Shah clashed with Iran's clergy, the Islamic class of Iran, and devout Muslims on many issues. In December 1928 he instituted a law requiring everyone (except Shia jurisconsults who had passed a special qualifying examination) to wear Western clothes which angered many religious figures in Iran and angered devout Muslims.
Reza Shah also encouraged women to discard the veil and stop hejab (head and body covering a woman under the rules of Islam). He announced that female teachers could not longer come to school with head coverings. One of his daughters reviewed a girls' athletic event with an uncovered head and this angered the religious right even more.
The devout were also angered by policies which allowed mixing of the sexes. Women were allowed to study in the colleges of law and medicine and in 1934 a law set heavy fines for cinemas, restaurants, and hotels that did not open doors to both sexes. He restricted public mourning observances to one day and required mosques to use chairs during these observances instead of the traditional sitting on the floors of mosques. This was indeed a detailed modernization agenda even if at times it was too much too soon and needed more time to be introduced and widely accepted.
However, many scholars have since expressed that Reza Shah's speeches to the parliament indicated that he had perceived the seeds of a new war in Europe and Iran needs to be economically, militarily, and politically better prepared to avoid being sucked into the war.
Reza Shah believed in independence and neutrality in matters of foreign relations and did not have any desire to participate in global polarization and worked to balance British influence with other foreigners and generally to diminish foreign influence in Iran altogether. Again this irritated the British immensely.
On 21 March 1935, Reza Shah had issued a decree asking foreign delegates to use the term Iran in formal correspondence in accordance with the fact that Persia was a term used for a country identified as Iran in the Persian language. It has however contributed more to the Iranian people than others, particularly its language. The name Iran means “Land of the Aryans”.
The British assumed that this may be somehow an indication of Iranian leader's desire to become closer with the Aryan race of Germany. Whether this was a deliberate indulgence by the British to demonize Reza Shah or simply an unintentional misunderstanding on the part of the British based on misleading ideas and ignorance as well as arrogance, still remains a hot topic of debate.
In 1931, Reza Shah refused to allow British Imperial Airways to fly in Persian airspace, instead giving the concession to German-owned Lufthansa Airlines and later surprised the British by unilaterally canceling the oil concession awarded William Knox D’Arcy (then called Anglo-Persian Oil Company), which was slated to expire in 1961.
The concession granted Persia (which what Iran used to be named) 16% of the net profits from AIOC oil operations. The Shah wanted 21%. Following a brief challenge by the British before the League of Nations, the British acquiesced. However in 1972 the Vice President of British Petroleum confessed that the British were taking more than 99% of the profits from Iranian oil and giving less than 1% to Iran - and even so, the 1% was directed towards British supporters in Iran rather than the whole population. The Iranians were not allowed to review or audit the accounting books of AIOC (the so called Anglo-Iranian Oil Company, now known as British Petroleum). The British regarded this as an "act of insult" and refused to accommodate this audit for the sake of accuracy and transparency. Sure enough, later it was quite evident that the British had lied and had been stealing the Iranian oil and were indeed in breach of the agreement made by the concession.
Reza Shah had previously hired American consultants to develop and implement Western-styled financial and administrative systems, which included the U.S. Economist, Dr. Arthur Millspaugh who acted as the nation's Finance Minister.
Reza Shah also purchased ships from Italy and hired Italians to teach his troops the intricacies of naval warfare. He also began bringing in hundreds of German technicians and advisors for various mining and roadwork projects. Mindful of the Persian’s long period of subservience to British Empire's enormous military power and the Russian brutal conduct as Iran's neighbor, Reza Shah was careful to avoid giving any one foreign nation too much control.
He also insisted that foreign advisors be employed by the Persian government so that they would not be answerable to foreign powers. This was based upon his experience with Anglo-Persian Oil Company which was owned and operated by the British government and had been causing problems for Iran for more than a quarter of a century.
In his campaign against foreign influence he annulled the 19th century capitulations to Europeans in 1928. Under these, Europeans in Iran had enjoyed the privilege of being subject to their own consular courts rather than to the Iranian judiciary.
The right to print money was moved from the British Imperial Bank to Iran's National Bank (Bank-i Melli Iran), as was the administration of the telegraph system from the Indo-European Telegraph Company to the Iranian government, in addition to the collection of customs by Belgian officials. He eventually fired Millspaugh, and prohibited foreigners from administering schools, owning land or traveling in the provinces without police permission.
To many Intellectual Iranians of the time (and even today), Reza Shah was indeed an Iranian hero and all his achievements were a testament to his strong character and love for Iran and her people.
Of course this is precisely what empires despise and find threatening: a sovereign nation's independence and desire for self-sufficiency.
When Britain declared war on Germany, it was bad news for Iran. Reza Shah's foreign policy, which had consisted essentially of playing the Soviet Union off against Britain, failed when those two powers joined in 1941 to fight the Germans and supply the Soviet forces with war material through Iran. Hence the two allies, along with United States, jointly attacked, invaded, and occupied the country in August 1941, with Franklin D. Roosevelt's blessings.
The British insisted that Reza Shah must abdicate and he remained as a prisoner in British territories, first in Mauritius, then in Durban and finally in Johannesburg, South Africa, where he died on July 26, 1944.
Today, the history has been repeating itself, at least somewhat.
The superpower of United States and the accommodating gang of bullies (Britain, France, and the coalition of bribed and coerced) are once again horrified of Iran's desire for independence, self-sufficiency, and self-rule. The United States spends more than $75 million per year to overthrow the Iranian government, against the Algiers Accord, and against every United Nations charter covering sovereignty of nations.
While United States built the first nuclear weapon, then proliferated (unintentionally through defection) to Russia, then deliberately proliferated to France and Britain to strengthen Europe against the Soviets, it now accuses Iran of wanting to acquire the knowledge to build nuclear weapons. US is joined by two of its major supporter, France and Britain, who themselves have been involved in proliferation of nuclear weapons to Israel. France provided Israel with nuclear technology in 1958 and their research reactor. Britain provided the nuclear fissile material, shipped through Norway, for the Israelis to build their nuclear weapons (estimated to be between 75 and 400 warheads).
Now U.S., France, and Britain accuse Iran of wanting to build nuclear weapons.
If you believe in justice and equality- then you would hope that Iran succeeds. If you believe that rights are only granted by U.S. and its coalition of bullies, then you would probably prefer that Iran remains a country unable to defend its rights.