In Yorkshire, the motive for sedition (7)
I believe the answer is:
treason
'sedition' is the definition.
(thesaurus)
'in yorkshire the motive' is the wordplay.
'in yorkshire' becomes 't' (Northern English pronunciation of 'the').
'the motive' becomes 'reason' (reason is a kind of motive).
't'+'reason'='TREASON'
'for' is the link.
(Other definitions for treason that I've seen before include "Criminal attempt to overthrow a government" , "Betrayal of the state" , "Serious crime" , "Betraying one's country" , "attempting to overthrow the king" .)