In addition to what has been said, Orwell was very concerned that the political process was being corrupted because the language used to express ideas was becoming increasing corrupted. (Here is a link to his essay http://www.mtholyoke.edu/acad/intrel/orwell46.htm --- I think it's must reading). One of the major themes of "1984" revolves around the creation of "Newspeak" which is really a vehicle for limiting the range of lanuage and, since we can only think in language, the range of our thought. Add to the control of language the control of information ("Who controls the present controls the past; who controls the past controls the future"), and you have a frightening picture of a world of people who think they are free, but have neither the language nor the information to BE free.
Orwell wrote 1984 alone on an icolated island as his last legacy. It is clear that he felt compelled to write the novel to serve as a warning of the perils of totalitarianism.
George Orwell was a democratic socialist and a conservative in the classical sense, which entails a belief in limited government, an isolationist (or at most, defensive) foreign policy, low taxes, resistance to drastic change, and a healthy respect for individual freedom. Quite different, in my opinion, from the moralistic authoritarianism that passes for "conservative" in America today, but let's not get into that...
Orwell wrote 1984 between 1944 and 1948, in the immediate aftermath of World War II. Europe had just witnessed a strain of totalitarianism unlike anything ever seen before or since. To Orwell, it was clear that modern government was capable not only of influencing people's actions, but of controlling their thoughts, making any sort of resistance impossible by definition. He feared that Britain, having been devastated by a stronger enemy almost to the point of ruin, would turn away from liberal democracy and embrace either fascism or socialism. 1984 indulges those fears, borrowing imagery from Hitler's Third Reich and Stalin's Soviet Union, so as to caution its readers against ideological extremism.