Help politician to conceal British tale of woe (3,5)
I believe the answer is:
sob story
'tale of woe' is the definition.
(I've seen this before)
'help politician to conceal british' is the wordplay.
'help' becomes 'SOS' (emergency abbreviation SOS).
'politician' becomes 'tory' (I've seen this before).
'to conceal' is an insertion indicator.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'sos'+'tory'='sostory'
'sostory' placed around 'b' is 'SOB-STORY'.
(Other definitions for sob story that I've seen before include "Pathetic tale" , "Account intended to evoke sympathy" , "A tale of woes" , "Tale to gain sympathy" , "Tear-jerking tale" .)