—An accident shall be deemed to arise out of and in the course of an employee's employment notwithstanding that he is at the time of the accident acting in contravention of the provisions of any law applicable to him, or of any orders given by or on behalf of his employer or that he is acting without instructions from his employer, if—

(a) the accident would have been deemed so to have arisen had the act not been done in contravention as aforesaid on or without instructions from his employer, as the case may be; and

(b) the act is done for the purpose of and in connection with the employer's trade or business.