Heralding British taking on US city planning policy? (9)
I believe the answer is:
Here is my best explanation:
'heralding' is the definition.
'british taking on us city planning policy?' is the subsidiary indication.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'taking on' says to put letters next to each other.
'us city' becomes 'la'.
'planning policy?' becomes 'zoning'.