Regulation 21 Offences due to fault of another person and defence of due diligence
Where the commission by any person of an offence under any of the provisions of these Regulations is due to the act or default of some other person, that other person shall be guilty of the offence; and a person may be charged with and convicted of the offence by virtue of this paragraph whether or not proceedings are taken against the first-mentioned person.
In any proceedings for an offence under any of the provisions of these Regulations, it shall, subject to paragraph (3), be a defence for the person charged to prove that that person took all reasonable precautions and exercised all due diligence to avoid the commission of the offence by himself or by a person under the person’s control.
If in any case the defence provided by paragraph (2) involves the allegation that the commission of the offence was due to an act or default of another person, or to reliance on information supplied by another person, the person charged shall not, without leave of the court, be entitled to rely on that defence unless—
at least seven days before the hearing; and
where the person charged has previously appeared before a court in connection with the alleged offence, within one month of his first such appearance,
that person has served on the prosecutor a notice in writing giving such information identifying or assisting in the identification of that other person as was then in his possession.
In paragraph (3) any reference to appearing before a court shall be construed as including a reference to being brought before a court.