Track down regularly overlooked Tory expert (5)
I believe the answer is:
trace
'track down' is the definition.
(I've seen this in another clue)
'regularly overlooked tory expert' is the wordplay.
'regularly overlooked' means one should take alternating letters (letters removed at regular intervals).
'expert' becomes 'ace' (ace can informally mean very good).
The alternating letters of 'tory' are 'tr'.
'tr'+'ace'='TRACE'
(Other definitions for trace that I've seen before include "a piece of harness" , "Find; copy; small amount" , "Vestige, hint" , "part of harness" , "Copy; describe; draw" .)