Bishop arrested by new Lancashire PC in force (7,6)
I believe the answer is:
special branch
'force' is the definition.
'bishop arrested by new lancashire pc' is the wordplay.
'bishop' becomes 'B' (chess abbreviation).
'arrested by' is an insertion indicator (inserted letters are held or arrested).
'new' indicates an anagram.
'lancashire'+'pc'='lancashirepc'
'lancashirepc' is an anagram of 'specialranch'.
'b' placed within 'specialranch' is 'SPECIAL BRANCH'.
'in' is the link.
(Other definitions for special branch that I've seen before include "counter-terrorist unit?" , "officers" , "Police department dealing with political security" , "Division of police dealing with political security" , "Police responsible for political security" .)