Spokesperson's unwelcome in the outskirts of Middlesbrough (5)
I believe the answer is:
mouth
'spokesperson's' is the definition.
(thesaurus)
'unwelcome in the outskirts of middlesbrough' is the wordplay.
'unwelcome' becomes 'out' (out can mean no longer desired or wanted).
'in the' indicates putting letters inside.
'outskirts of' means to remove the middle letters.
'middlesbrough' with its centre taken out is 'mh'.
'out' placed inside 'mh' is 'MOUTH'.
(Other definitions for mouth that I've seen before include "End of river" , "River outlet" , "Opening of a bay" , "Where a river enters the sea" , "chops" .)