Hostilities having start delayed by English politician (6)
I believe the answer is:
attlee
'politician' is the definition.
(Clement Attlee)
'hostilities having start delayed by english' is the wordplay.
'hostilities' becomes 'battle'.
'having start delayed' means to remove the first letter.
'by' means one lot of letters go next to another.
'english' becomes 'e' (abbreviation).
'battle' with its initial letter removed is 'attle'.
'attle'+'e'='ATTLEE'
(Other definitions for attlee that I've seen before include "Prime minister nineteen forty five to fifty one" , "Clement -, UK PM" , "Clement --, former PM" , "Granny Smiths perhaps" , "Clement ..., former British prime minister" .)