Facility introduced by Civil Service comes to an end (6)
I believe the answer is:
ceases
'comes to an end' is the definition.
('cease' can be a synonym of 'come to an end')
'facility introduced by civil service' is the wordplay.
'facility' becomes 'ease' (I've seen this before**).
'introduced by' is an insertion indicator (I've seen this in other clues).
'civil service' becomes 'cs'.
'ease' placed inside 'cs' is 'CEASES'.
(Other definitions for ceases that I've seen before include "Stops or discontinues" , "stops working" , "Finishes" , "Terminates" , "Discontinues, ends" .)