Issue uniform in Officer Training Corps Cockney’s in (7)
I believe the answer is:
outcome
'issue' is the definition.
(thesaurus)
'uniform in officer training corps cockney's in' is the wordplay.
'uniform' becomes 'u' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' is an insertion indicator.
'officer training corps' becomes 'otc' (short for Officers' Training Corps).
'cockney's in' becomes 'ome' ('home' - 'he's in' can mean 'he's home' - said with a cockney accent, dropping the 'H').
'u' inserted within 'otc' is 'outc'.
'outc'+'ome'='OUTCOME'
(Other definitions for outcome that I've seen before include "consequences" , "Consequence, upshot" , "Consequence, effect" , "Eventuality" , "answer" .)