Writer upset British stars in trade restriction (7)
I believe the answer is:
embargo
'trade restriction' is the definition.
(I've seen this in another clue)
'writer upset british stars' is the wordplay.
'writer' becomes 'me' (the person who wrote the clues).
'upset' says the letters should be written in reverse.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'stars' becomes 'argo' (I've seen this before).
'me' written backwards gives 'em'.
'em'+'b'+'argo'='EMBARGO'
'in' acts as a link.
(Other definitions for embargo that I've seen before include "Eg, Rambo? (anag)" , "Official prohibition as on trade" , "Ban or restraint on trade" , "Commercial ban" , "Trading ban" .)