Time for a break in Bury campaign (12)
I believe the answer is:
intermission
'time for a break' is the definition.
(break in a performance)
'bury campaign' is the wordplay.
'bury' becomes 'inter' (to inter is to put into the ground).
'campaign' becomes 'mission' (campaign can mean a task or mission).
'inter'+'mission'='INTERMISSION'
'in' acts as a link.
(Other definitions for intermission that I've seen before include "Break; respite" , "Pause, break" , "Theatre's half-time" , "Interval" , "Entr'acte" .)