Father, running through London (6)
I believe the answer is:
thames
'father running through london' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
Can you help me to learn more?
(Other definitions for thames that I've seen before include "The Ma's in the river" , "capital banker" , "Shipping forecast area" , "River of southern England" , "London river" .)