Composed dirge about England's first old northerner (7)
I believe the answer is:
geordie
'northerner' is the definition.
(term for a person from Tyneside in NE England)
'composed dirge about england's first old' is the wordplay.
'composed' is an anagram indicator.
'about' means one lot of letters goes inside another.
'england' becomes 'E' (short for England).
'first old' becomes 'o' (1st letter of 'old').
'dirge' is an anagram of 'grdie'.
'e'+'o'='eo'
'grdie' going around 'eo' is 'GEORDIE'.
(Other definitions for geordie that I've seen before include "Newcastle-born?" , "Newcastle person" , "Inhabitant of Tyneside" , "Newcastle dialect" , "Native of Tyneside" .)