Watchful about central Kilburn, he was nearer Victoria (6)
I believe the answer is:
albert
'he was nearer victoria' is the definition.
The definition suggests a singular noun which matches the answer.
'watchful about central kilburn' is the wordplay.
'watchful' becomes 'alert ' (similar in meaning).
'about' indicates putting letters inside.
'central' means to look at the middle letters.
The middle of 'kilburn' is 'b'.
'alert' placed around 'b' is 'ALBERT'.
Can you help me to learn more?
(Other definitions for albert that I've seen before include "Prince with 24" , "Old watch chain" , "watch may depend on it" , "M [MUSEUM] with 18 [VICTORIA]" , "Prince of Monaco" .)