(1)  If a person in custody does not have a knowledge of the English language that is sufficient to enable the person to understand the questioning or investigation, the police officer conducting the investigation must, before any questioning or investigation under section 4 may commence, arrange for the presence of a competent interpreter and defer the questioning or investigation until the interpreter is present.

(2)  This section does not apply to questioning or investigation in connection with an offence under –

(a) section 4 , 6 or 14 of the Road Safety (Alcohol and Drugs) Act 1970 ; or

(b) section 13(1) , 16(1) , 21(2) , 22(3) , 24(2) , 26(2) , 28(3) , 33(3) or 38(3) of the Marine Safety (Misuse of Alcohol) Act 2006 .