Outspoken historian in border city (8)
I believe the answer is:
carlisle
'border city' is the definition.
(English city near the Scottish border)
'outspoken historian' is the wordplay.
'outspoken' indicates a 'sounds like' (homophone) clue.
'historian' becomes 'carlyle' (Thomas Carlyle).
'carlyle' is a homophone of 'CARLISLE'.
'in' is the link.
(Other definitions for carlisle that I've seen before include "Administrative centre of Cumbria" , "England's Border City" , "City in Cumbria" , "Cumbrian city where Royalists surrendered in 1645" , "cathedral city" .)