The information below is taken from an article in the Atlantic Magazine January/February 2017 issue. They stated that their thoughts were taken from this book: Letters of Note.
Aldous Huxley to George Orwell: My Dystopia Is Better Than Yours
On October 21, 1949, a few months after the publication of Nineteen Eighty-Four, George Orwell received a letter from Aldous Huxley, whose Brave New World had been published 17 years earlier. Huxley concludes:
“Within the next generation, I believe that the world’s rulers will discover that infant conditioning and narco-hypnosis are more efficient as instruments of government than clubs and prisons and that the lust for power can be just as completely satisfied by suggesting people into loving their servitude as by flogging and kicking them into obedience. In other words, I feel that the nightmare of Nineteen Eighty-Four is destined to modulate into the suffering of a world having more resemblance to that which I imagined in Brave New World.
The change will be brought about due to a felt need for increased efficiency. Meanwhile, there may be a large-scale biological and atomic war—in which case we shall have nightmares of other and scarcely imaginable kinds."