Military command certainly abandoned after first of evacuations (4,4)
I believe the answer is:
eyes left
'military command' is the definition.
(I've seen this before)
'certainly abandoned after first of evacuations' is the wordplay.
'certainly' becomes 'yes' (both can be used to answer in the affirmative).
'abandoned' becomes 'left' (leave can mean to abandon).
'after' is a charade indicator (letters next to each other).
'first of evacuations' becomes 'e' (1st letter of 'evacuations').
'yes'+'left'='yesleft'
'yesleft' after 'e' is 'EYES LEFT'.
(Other definitions for eyes left that I've seen before include "army command" , "Marching command" , "Instruction to soldiers to look to one side" , "military command" .)