Where an employer is charged with an offence against this Act, he shall be entitled, upon complaint duly made by him, to have any other person whom he charges as the actual offender, brought before the Court at the time appointed for hearing the charge; and if, after the commission of the offence has been proved, the employer proves to the satisfaction of the Court--

(a) that he has used due diligence to enforce the execution of this Act, and

(b) that the said other person committed the offence in question without his knowledge, consent or connivance,

that other person shall be convicted of the offence and shall be liable to the like punishment as if he were the employer and the employer shall be discharged:

Provided that in seeking to prove, as aforesaid, the employer may be examined on oath, and the evidence of the employer or his witness, if any, shall be subject to cross-examination by or on behalf of the person whom the employer charges as the actual offender and by the prosecution.