Stall ridiculous conservatives' lies (4,7)
I believe the answer is:
'lies' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'stall ridiculous conservatives'' is the wordplay.
'ridiculous' indicates an anagram.
'conservatives'' becomes 'tories'' (informal term for the Conservative Party).
'stall' is an anagram of 'talls'.
Can you help me to learn more?
(Another definition for tall stories that I've seen is " Improbable tales".)