Communist returns via English city (5)
I believe the answer is:
derby
'english city' is the definition.
(I've seen this before)
'communist returns via' is the wordplay.
'communist' becomes 'red' (red is a kind of communist).
'returns' shows that the letters should be reversed in order.
'via' becomes 'by'.
'red' in reverse letter order is 'der'.
'der'+'by'='DERBY'
(Other definitions for derby that I've seen before include "Cathedral city on the River Derwent" , "Hat, race and local match" , "Commotion" , "Epsom horse race" , "... and after 8 [STATE = KENTUCKY] , meeting" .)