Inko - erm yes a rule is not a law
the wiki says that various legal systems recognise this
I am pretty sure ours doesnt
In Mr WHicher's case if you recollect the murderess has confessed to an Anglican priest, and HE refuses to testify. IN real life the ArchB of C writes to the Times and reminds the readership that there are 7 sacraments in the Anglican Church of which auricular confession is one.
see also
http://en.wikipedia.org/wiki/Constance_Kent