Left, incensed by the organisation (3,5)
I believe the answer is:
red cross
'organisation' is the definition.
(Red Cross is an example)
'left incensed by' is the wordplay.
'left' becomes 'red' (red can informally mean communist).
'incensed by' becomes 'cross' (I can't explain this - if you can you should give a lot more credence to this answer).
'red'+'cross'='RED-CROSS'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for red cross that I've seen before include "seen flying across the country on April twentythird" , "Medical group" , "Famous emblem" , "International organisation to help wounded in war" , "International oranisation for treatment of wounded in war" .)