Uproar about a fashionable black emblem used for the NHS (7)
I believe the answer is:
rainbow
'emblem used for the nhs' is the definition.
(rainbows can represent the National Health Service)
'uproar about a fashionable black' is the wordplay.
'uproar' becomes 'row' (I've seen this in another clue).
'about' indicates putting letters inside.
'a fashionable' becomes 'ain' (I can't explain this - if you can you should give a lot more credence to this answer).
'black' becomes 'b' (as in pencil classifications).
'ain'+'b'='ainb'
'row' enclosing 'ainb' is 'RAINBOW'.
Can you help me to learn more?
(Other definitions for rainbow that I've seen before include "Light effect in sky" , "Natural multicoloured arc" , "Coloured arc in the sky" , "weather feature" , "colours in the sky" .)