Leave the outskirts of Seville with upper-class twit (3,3)
I believe the answer is:
set off
'leave' is the definition.
(set off can mean to depart)
'outskirts of seville with upper-class twit' is the wordplay.
'outskirts of' means to remove the middle letters.
'with' means one lot of letters go next to another.
'upper-class twit' becomes 'toff' (term for an upper-class person).
'seville' with its centre taken out is 'se'.
'se'+'toff'='SET-OFF'
'the' is the link.
(Other definitions for set off that I've seen before include "radio with no reception" , "Commence journey or detonate" , "Begin journey or cause to ignite" , "Commence journey or explode bomb" , "Explode; start journey" .)