The provisions of this Part of this Act down to the end of section 24 shall have effect for the purpose of securing that, as regards mode of trial, there are only three classes of offence, namely—
(a)offences triable only on indictment;
(b)offences triable only summarily ; and
(c)offences triable either way,
for laying down a single procedure applicable to all cases where a person who has attained the age of seventeen appears or is brought before a magistrates' court on an information charging him with an offence which is triable either way, and for related purposes.