Impact of Tory diplomacy (7)
I believe the answer is:
contact
'impact' is the definition.
(thesaurus)
'tory diplomacy' is the wordplay.
'tory' becomes 'con' (abbreviation for conservative).
'diplomacy' becomes 'tact' (tact can mean diplomacy or sensitivity).
'con'+'tact'='CONTACT'
'of' acts as a link.
(Other definitions for contact that I've seen before include "securing current passage" , "Meeting" , "Communication" , "Juxtaposition" , "Get in touch with" .)