Passes over the Guardian's standard (7)
I believe the answer is:
colours
'standard' is the definition.
(colours can mean a flag or standard)
'passes over the guardian's' is the wordplay.
'passes' becomes 'cols' (a col is a mountain pass).
'over' is an insertion indicator.
'the guardian's' becomes 'our' (belonging to the newspaper the puzzle is part of).
'cols' placed around 'our' is 'COLOURS'.
(Other definitions for colours that I've seen before include "Red and blue" , "flag" , "Shades" , "Hues, tints" .)