What may beat the blues for Baron Goldsmith (6)
I believe the answer is:
prozac
'what may beat the blues' is the definition.
(anti-depressant)
'for baron goldsmith' is the wordplay.
'for' becomes 'pro' (as in being 'pro' something).
'baron goldsmith' becomes 'Zac' (politician Zac Goldsmith).
'pro'+'zac'='PROZAC'
(Other definitions for prozac that I've seen before include "medication" , "Controversial antidepressant" , "Common antidepressant drug" , "Upper" , "Anti-depressant trade mark" .)