Regarding a city, England's capital is cultured (6)
I believe the answer is:
urbane
'cultured' is the definition.
(synonyms)
'regarding a city england's capital is' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is present in the answer.
'city' could be 'ur' (ancient Sumerian city state) and 'ur' is located in the answer.
'is' could be 'be' and 'be' is located in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for urbane that I've seen before include "Cultured" , "Unbare, being suave." , "Smooth-mannered" , "Suavely elegant" , "Sophisticated and elegant - sounds citified" .)