Have you got the keys?

As I understand it, according to the BCP and the canons, in the dear old C of E, the presbyter has the power of the keys. He is to excommunicate gross notorious unrepentant sinners.

But he must notify the diocesan bishop who must give an opportunity for an interview and who may then give a ruling which the presbyter is to follow. The Bishop has a master or skeleton key.

Has the presbyter lost the power of the keys? Is this a good, right or acceptable system?

Texts on the power of the keys (and excommunication) most welcome too.