Whether or not adjacent to London, it's in Ireland (5)
I believe the answer is:
derry
'ireland' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see a link between them that I don't see?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for derry that I've seen before include "Ulster city" , "'The London - - Air' (mus.)" , "Port" .)