Left at jail without old locker (8)
I believe the answer is:
latchkey
'locker' is the definition.
(a latchkey locks something)
'left at jail without old' is the wordplay.
'left at' becomes 'lat' (I can't justify this - if you can you should give a lot more credence to this answer).
'jail' becomes 'chokey' (chokey can informally mean prison).
'without' suggests deleting specific letters.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'chokey' with 'o' taken out is 'chkey'.
'lat'+'chkey'='LATCHKEY'
(Other definitions for latchkey that I've seen before include "Common device to open outer door" , "A supposed freedom from domestic restrictions" , "Front door opener (for children with absent parents?)" , "Sort of self-reliant child" , "Describes a child who returns to an empty home" .)