No confession made by any person whilst he is in the custody of a police-officer, unless it be made in the immediate presence of a [Magistrate] , shall be proved as against such person.[Explanation. - In this section "Magistrate" does not include the head of a village discharging magisterial functions in the presidency of Fort St. George [* * *] or elsewhere, unless such headman is a Magistrate exercising the powers of a Magistrate under the [Code of Criminal Procedure. 1882 (10 of 1882) ] .]