English in British state work hard (6)
I believe the answer is:
beaver
'work hard' is the definition.
(I've seen this before)
'english in british state' is the wordplay.
'english' becomes 'E' (abbreviation).
'in' means one lot of letters goes inside another.
'british' becomes 'b' (abbreviation e.g. in BBC).
'state' becomes 'aver' (both can mean to declare).
'b'+'aver'='baver'
'e' placed within 'baver' is 'BEAVER'.
(Other definitions for beaver that I've seen before include "Brown, furry rodent" , "Small animal that builds dams on rivers" , "Lodge-making rodent" , "Dam-building animal" , "Furry animal, lives in lodge and builds dams" .)