Admission of a tax cut by Conservative (6)
I believe the answer is:
access
'admission' is the definition.
(thesaurus)
'a tax cut by conservative' is the wordplay.
'tax' becomes 'cess' (I've seen this before).
'cut by' means one lot of letters goes inside another.
'conservative' becomes 'c' (abbreviation commonly used in UK politics).
'cess' placed around 'c' is 'ccess'.
'a'+'ccess'='ACCESS'
'of' is the link.
(Other definitions for access that I've seen before include "drive, perhaps" , "Doorway" , "Retrieve information" , "Means of entry, passage" , "Means to enter a place" .)