What may be banned in summer is tights and slippers accompaniment (8)
I believe the answer is:
hosepipe
'what may be banned in summer' is the definition.
'tights and slippers accompaniment' is the wordplay.
'tights' becomes 'hose' ('hose' can be a synonym of 'tights').
'and' is a charade indicator (letters next to each other).
'slippers accompaniment' becomes 'pipe' (as in the phrase 'pipe-and-slipper').
'hose'+'pipe'='HOSEPIPE'
'is' is the link.
(Other definitions for hosepipe that I've seen before include "Flexible watering tube" , "Firefighting equipment" , "it will water garden" , "Watering device" , "gardening aid" .)