George Orwell coined this phrase in the third paragraph of the first chapter of his novel “1984.”
He writes, “It was one of those pictures which are so contrived that the eyes follow you about when you move. BIG BROTHER IS WATCHING YOU…”
Later it appeared on posters and televisions as a political slogan. This is a political satire and Big Brother in this story is the supreme authority of a totalitarian state called Oceania where “the Party” has the highest command over people.
The phrase refers to the surveillance of Big Brother with listening devices and cameras in a totalitarian society, where Big Brother is the head of the totalitarian regime.
Everyone in this society is under the surveillance of the authorities, which reminds people of an endless catchphrase “Big Brother is watching You” showing a dictator’s mindset of a Big Brother.
Generally, the idea conveys a line of propaganda, meaning citizens have to follow what a dictatorial government wants them to do, and if they do not, Big Brother will know, as it spies on them all the time.