Small country on radar in revolt (7)
I believe the answer is:
andorra
'small country' is the definition.
(Andorra is a small European country)
'on radar in revolt' is the wordplay.
'in revolt' indicates an anagram.
'on'+'radar'='onradar'
'onradar' is an anagram of 'ANDORRA'.
(Other definitions for andorra that I've seen before include "Small republic between Spain and France" , "Principality in SW Europe" , "Small European country" , "Self-governing principality in Pyrenees" , "Catalan state" .)