British party travel to see African river (5)
I believe the answer is:
congo
'african river' is the definition.
(I've seen this before)
'british party travel' is the wordplay.
'british party' becomes 'Con' (abbreviation for Conservative Party).
'travel' becomes 'go' (synonyms).
'con'+'go'='CONGO'
'to see' is the link.
(Other definitions for congo that I've seen before include "African river and region" , "African republic" , "former African nation" , "flower" , "Africa's second longest river" .)