A river in Swiss capital or British city (8)
I believe the answer is:
aberdeen
'british city' is the definition.
(I've seen this before)
'a river in swiss capital' is the wordplay.
'river' becomes 'Dee' (River Dee).
'in' indicates putting letters inside.
'swiss capital' becomes 'bern' (capital of Switzerland).
'dee' inserted into 'bern' is 'berdeen'.
'a'+'berdeen'='ABERDEEN'
'or' is the link.
(Other definitions for aberdeen that I've seen before include "Scottish E. coast city" , "Granite City of Scotland" , "city in Europe" , "football club" , "PM, resigned over Crimea" .)