A nationalist idiot in Belgian city (7)

I believe the answer is:

antwerp

'belgian city' is the definition.
(I've seen this before)

'a nationalist idiot' is the wordplay.
'nationalist' becomes 'N' (abbreviation in politics).
'idiot' becomes 'twerp' (I've seen this before).
'a'+'n'+'twerp'='ANTWERP'

'in' acts as a link.

(Other definitions for antwerp that I've seen before include "foreign city" , "New part of Dutch city" , "Major European port" , "Van Dyck birthplace" , "North Sea port" .)

I've seen this clue in The Everyman puzzle in The Observer.

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