Mood sours in the queues: such long journeys to the supermarket (4,5)
I believe the answer is:
food miles
'long journeys to the supermarket' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'mood sours in the queues' is the wordplay.
'sours' indicates anagramming the letters (the letters must sour or go bad).
'in the' indicates putting letters inside.
'queues' becomes 'files' (as in single file).
'mood' anagrammed gives 'oodm'.
'oodm' going into 'files' is 'FOOD MILES'.
'such' is the link.
Can you help me to learn more?
(Another definition for food miles that I've seen is " journey from plot to pot?".)