1. Where a statement is admitted as evidence in criminal proceedings by virtue of Part II—
(a)any evidence which, if the person making the statement had been called as a witness, would have been admissible as relevant to his credibility as a witness shall be admissible for that purpose in those proceedings;
(b)evidence may, with the leave of the court, be given of any matter which, if that person had been called as a witness, could have been put to him in cross-examination as relevant to his credibility as a witness but of which evidence could not have been adduced by the cross-examining party; and
(c)evidence tending to prove that that person, whether before or after making the statement, made (whether orally or not) some other statement which is inconsistent with it shall be admissible for the purpose of showing that he has contradicted himself.