Design of prison must include European court examiner (9)
I believe the answer is:
inspector
'examiner' is the definition.
('inspector' can be a synonym of 'examiner')
'design of prison must include european court' is the wordplay.
'design of' is an anagram indicator (I've seen this in other clues).
'must include' indicates putting letters inside.
'european' becomes 'e' (abbreviation e.g. EU).
'court' becomes 'ct'.
'prison' anagrammed gives 'inspor'.
'e'+'ct'='ect'
'inspor' placed around 'ect' is 'INSPECTOR'.
(Other definitions for inspector that I've seen before include "leading rank" , "senior cop" , "auditor" , "Police officer" , "controller" .)