Effective ruler of the street? (6)

I believe the answer is:

regent

I'm a little stuck... Click here to teach me more about this clue!

'effective ruler' is the definition.
'regent' can be an answer for 'ruler' (regent is a kind of ruler). I am unsure of the 'effective' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for regent that I've seen before include "Governor" , "Queen possibly" , "acting chief" , "being temporarily in charge" , "Someone ruling on behalf of another" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app