'A' rings up the police station and informs the Duty Officer that he has murdered his wife because she…

A statement to a police officer that amounts to a confession is excluded by section 25 of the Evidence Act, whether or not the maker was in custody. In Aghnoo Nagesia v State of Bihar (1965) the Supreme Court held that when an accused lodges a confessional first information report, only the part showing that he was its maker is admissible, as his conduct. So the statement is "Admissible only to the extent that 'A' was the informant"; his presence at the house and knowledge of the murder form part of the confession and are excluded.

Current law: BSA section 23(1) retains the police-confession exclusion, subject to section 170 savings for pending proceedings.