George Orwell drew on his own W.W.II. experiences working with the BBC to demonstrate the power of propaganda to bolster the political power of those in control. In Oceania, patriotic fervour for the Party is linked to the perpetual state of war, with enables those in power to claim emergency powers over their populace.
The novel's protagonist is well aware of the falsification of statistics and data used to dupe the populace and make them compliant.
Readers of the novel when it was first published, would be familiar with the use of posters during the war, reinforcing that Orwell was making use of contextual influences to make his dystopic vision credible.