Signal extreme distress about British Conservative's pitiful tale (3,5)
I believe the answer is:
sob story
'pitiful tale' is the definition.
(I've seen this before)
'signal extreme distress about british conservative's' is the wordplay.
'signal extreme distress' becomes 'sos' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' means one lot of letters goes inside another.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'conservative' becomes 'tory' (informal term for a Conservative Party member).
'sos' placed around 'b' is 'sobs'.
'sobs'+'tory'='SOB-STORY'
Can you help me to learn more?
(Other definitions for sob story that I've seen before include "Tale of misfortune" , "Tear-jerking account" , "Tale to gain sympathy" , "appeal to emotions" , "Sentimental tale designed to arouse sympathy" .)