Certificates to accompany claims for payment

A contractor shall not be entitled to payment of any money which would otherwise be payable under the terms of contract in respect of the work and labour performed in the execution of the contract unless and until he shall have filed together with his claim for payment a certificate– (a) showing the rates of wages and hours of labour of the various classes of workmen employed in the execution of the contract; (b) whether any wages in respect of the said work and labour remains in arrears; and (c) that all the labour conditions of the contract have been duly complied with.