Go Conservative - nothing to lose! (3)
I believe the answer is:
try
'go' is the definition.
(I've seen this before)
'conservative nothing to lose' is the wordplay.
'conservative' becomes 'tory' (I've seen this before).
'nothing' becomes 'o' (looks like zero - 0).
'to lose' is a deletion indicator.
'tory' with 'o' removed is 'TRY'.
(Other definitions for try that I've seen before include "Go" , "Examine" , "Attempt a score" , "Endeavour" , "Gorse" .)