Hand over alcohol -- it'll help when leaving the EU (8)
I believe the answer is:
passport
'it'll help when leaving the eu' is the definition.
'hand over alcohol' is the wordplay.
'hand over' becomes 'pass' (**).
'alcohol' becomes 'port' (port is a kind of alcohol).
'pass'+'port'='PASSPORT'
(Other definitions for passport that I've seen before include "entry permit?" , "that may gain acceptance" , "papers" , "the key to success?" , "Document to allow entry to another country" .)