Newcastle's finest former PM discovered Wales (5,3)
I believe the answer is:
brown ale
'newcastle's finest former' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'pm discovered wales' is the wordplay.
'pm' becomes 'brown' (I have seen 'Former PM ' mean 'brown' so perhaps 'pm' could also mean 'brown').
'discovered' indicates the central letters (dis-covered - outer letters removed).
The centre of 'wales' is 'ale'.
'brown'+'ale'='BROWN ALE'
Can you help me to learn more?
(Other definitions for brown ale that I've seen before include "bottled beer" , "Dark, malty beer" , "Dark, mild beer" , "Type of beer" , "Noble war (anag) - drink" .)