85(1)
Where any employer in the course of or for the purposes of his trade or business contracts with a contractor for the execution by or under the contractor of the whole or any part of any work which is ordinarily part of the trade or business of the employer, the employer shall be liable to pay to any employee employed in the execution of the work any compensation, which he would have been liable to pay if that employee had been immediately employed by him; and that the amount of compensation shall be calculated with reference to the wages of the employee under the employer by whom he is immediately employed.