Capital found on the Thames? (7)
I believe the answer is:
belfast
'capital' is the definition.
(I know that Belfast is a national capital)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for belfast that I've seen before include "City on the Lagan" , "Capital of Northern Ireland" , "N. Ireland city" , "Northern Ireland home to Queen's University" , "NI city" .)