Here is what roger waters said of "not now john". ("john" is a british word much like "jack" or "buddy" in the states).

INTERVIEWER: "not now john" is about over ambitions & drive for money and winning...blind ambitions to best the "wily japanese" and to conqueor the russian bear"

ROGER:yes, but never mind the russian bear, what about the other members of the human race?...wait until they start trying to compete, and that's most of us. There are lots more of them than there are of us. There are more of the third world than there are of the old and new worlds. And as soon as they get TVs, they're going to get well up-tight. In fact, they may well say, "You've had your go, we want our go now." it's that kind of 'more.'

INTERVIEWER: Would you say that the personality/persona of the singer in "not now john" has the same mentality or character as in "have a cigar?"...We're all put together as a team.

ROGER: Well, yes. You've done your homework!