Everything extremely suspect in Conservative's unlikely tale (4,5)
I believe the answer is:
tall story
'unlikely tale' is the definition.
(I've seen this before)
'everything extremely suspect in conservative's' is the wordplay.
'everything' becomes 'all' (I've seen this before).
'extremely' says to hollow out the word (remove centre letters).
'in' means one lot of letters goes inside another.
'conservative' becomes 'tory' (I've seen this before).
'suspect' with its middle taken out is 'st'.
'all'+'st'='allst'
'allst' inserted within 'tory' is 'TALL STORY'.
(Other definitions for tall story that I've seen before include "unreliable account" , "Incredible account" , "Exaggerated and incredible yarn" , "Lie" , "Unbelievable yarn" .)