Uproar about performance overturning working-class symbol (4,3)
I believe the answer is:
flat cap
'working-class symbol' is the definition.
(I've seen this before)
'uproar about performance overturning' is the wordplay.
'uproar' becomes 'flap' (I've seen this in another clue).
'about' indicates putting letters inside.
'performance' becomes 'act' (act is a kind of performance).
'overturning' is a reversal indicator.
'act' written backwards gives 'tca'.
'flap' enclosing 'tca' is 'FLAT-CAP'.
(Other definitions for flat cap that I've seen before include "Headgear (of the working class?)" , "Style of headgear" , "Type of hat" , "working-class symbol" , "> lid" .)