Quickly has set fire to flipping yard (7)
I believe the answer is:
hastily
'quickly' is the definition.
(I've seen this before)
'has set fire to flipping yard' is the wordplay.
'set fire' becomes 'lit' (I've seen this in other clues).
'to flipping' says the letters should be written in reverse.
'yard' becomes 'y'.
'lit' in reverse letter order is 'til'.
'has'+'til'+'y'='HASTILY'
(Other definitions for hastily that I've seen before include "Quickly" , "In a hurried manner" , "Rapidly" , "Hurriedly" .)