British space vessel with provisions for storage (5,8)
I believe the answer is:
broom cupboard
'storage' is the definition.
'british space vessel with provisions' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'space' becomes 'room' (room is a kind of space).
'vessel' becomes 'cup' (I've seen this in other clues).
'with' is a charade indicator (letters next to each other).
'provisions' becomes 'board' (as in food provided by an overnight establishment).
'b'+'room'+'cup'+'board'='BROOM CUPBOARD'
'for' is the link.
(Another definition for broom cupboard that I've seen is " Storage space for housework items".)