Last performance - effectively as Desmond, N? (8)
I believe the answer is:
swansong
'last performance' is the definition.
(I've seen this before)
'effectively as desmond n?' is the wordplay.
I cannot quite understand how this works, but
'as' could be 'so' (I've seen this in other clues) and 'so' is located in the answer.
'n?' could be 'n' and 'n' is found within the answer.
The remaining letters 'swang' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for swansong that I've seen before include "Final appearance" , "Final work or performance" , "Last call" , "last performance" , "Last act" .)