Hemmed in - small songbird caught in outbuilding (8)
I believe the answer is:
stitched
'hemmed' is the definition.
(I've seen this in another clue)
'small songbird caught in outbuilding' is the wordplay.
'small songbird' becomes 'tit' (I've seen this in another clue).
'caught' becomes 'c' (cricket abbreviation).
'in' means one lot of letters goes inside another.
'outbuilding' becomes 'shed' (shed is a kind of outbuilding).
'tit'+'c'='titc'
'titc' going into 'shed' is 'STITCHED'.
'in' is the link.
(Other definitions for stitched that I've seen before include "Attached with thread" , "Made use of the needle" , "after action in theatre?" , "Used a needle" , "Joined up" .)