On October 12, 1955, the plain!Iff filed an application before the Superintendent of Sales Tax, Dhanbad for refund of the tax paid by him. This claim was made on the basis of the appellate order. On January 30, 1956, Sales Tax Laws Validation 0 Ordinance (No. 3 of 1956) was issued which was followed up by Sales Tax Laws Validation Act, 1956. The scope of this Act was considered by this Court in M. P. V. Sundararamier & Co. v. The State of Andhra Pradesh and Anr. ('). Therein this Court by majority held that the Sales Tax Laws Validation Act. 1 956 is in substance one lifting the ban on taxation of inter-State sales and is within the authority conferred on Parliament under Art. E 286(2) and further that under that provision it was competent to Parliament to enact a Jaw with retrospective operation. Therein this Court further held that s. 2 of the Sales Tax Laws Validation Act validates not only levies already coll,ected but also authorised the imposition of tax on sales falling within the explanation which had taken place within the period specified in. s. 2. It was also F held that ihe Act was .not a temporary one though its operation is limited to sales taking place within a specified period. Evidently because of the Sales-tax Laws Validation Ordinance and the Sales Tax Laws Validation Act, the Superintendent of Sales Tax. Dhanbad did not comply with the demands made by the plaintiff. Thereafter the plaintiff issued to the defendant a notice on June G 7, 1958 calling upon the defendant to refund the amount paid by it with interest. The defendant ignored that demand. Then the plaintiff filed 'a suit on the original side of the Calcutta High Court claiming a sum of Rs. 13,176/69 P. with interest and costs. In the plaint the plaintiff put forward three different grounds as affording him a cause of action to institute the suit on the original side' of the High Court. They are : ( 1) that the. pay, H ments in question were made by it under a bona fide mistake of law namely that it was liable to pay sales tax to the defendant (!) [1955] 2 S.C'.R. 603 (2) {1958] S.C.R. 1422. I l-L119SuoC!/72