... its members to support latest of Boris's lies (7)
'lies' is the definition.
(story is a kind of lie)
'its members to support latest of boris's' is the wordplay.
I cannot really see how this works, but
'to' is within the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for stories that I've seen before include "See 21", "House sections", "Floors", "Accounts", "Lies".)