Boris's ending politicians' lies (7)
I believe the answer is:
stories
'lies' is the definition.
(I know this)
'boris's ending politicians'' is the wordplay.
'ending' suggests the final letters (the ending of the word).
'politicians'' becomes 'tories' (I've seen this before).
The last letter of 'boris' is 's'.
's'+'tories'='STORIES'
(Other definitions for stories that I've seen before include "See 12" , "Tales" , "See 21" , "For example, scoops" , "Accounts" .)