Independent Irish parliament's return is epic (5)
I believe the answer is:
iliad
'is epic' is the definition.
(I've seen this before)
'independent irish parliament's return' is the wordplay.
'independent' becomes 'i'.
'irish parliament' becomes 'dail' (I've seen this before).
'return' shows that the letters should be reversed in order.
'dail' reversed gives 'liad'.
'i'+'liad'='ILIAD'
(Other definitions for iliad that I've seen before include "epic work" , "Epic poem attributed to Homer" , "Greek epic poem about the Trojan War" , "Work by Homer" , "set of books" .)