Establishment’s about to move right in response (8)
I believe the answer is:
reaction
'right in response' is the definition.
'reaction' can be an answer for 'response' (synonyms). I am not certain of the 'right in' bit.
'establishment's about to move' is the wordplay.
'establishment's about' becomes 're' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to move' becomes 'action'.
're'+'action'='REACTION'
Can you help me to learn more?
(Other definitions for reaction that I've seen before include "Creation found in response to event" , "Force" , "Into care (anag)" , "Result of stimulus" , "Chemical change or backlash" .)