Blake, maybe, is going to one in the morning (7)
I believe the answer is:
william
'blake maybe' is the definition.
(poet William Blake)
'is going to one in the morning' is the wordplay.
'is going to' becomes 'will' (John is going to eat/John will eat).
'one in the morning' becomes 'Iam' (1am).
'will'+'iam'='WILLIAM'
(Other definitions for william that I've seen before include "Boy's name" , "Bill" , "I am a weakish speller (anag) -- author" , "-- Caxton, early printer" , "- - Wordsworth" .)