clear blue water
A separation between rivals or opponents. Primarily heard in UK. There's no clear blue water between the candidates now—the race is as tight as can be.
clear blue water
an obvious and decisive gap between you and your rivals. British The expression originated in the 1990s as a political slogan characterizing the ideological gap between the British Conservative party (whose traditional colour is blue) and its political opponents, which right-of-centre Conservatives wished to be as wide as possible.