The petitioner is a partnership firm having its place of business at Calcutta. The petitioner undertakes execution of contracts for supply, erection and commissioning of electrical equipments in different States. On 7.2.86, it entered into an agreement with the Executive Engineer, Micro Hyde! Investigation Division, Government of Tripura for execution of the work of "supply, erection and commissioning of 66/11 K.V.6.3 MVA Sub-Station at Sonamura in the State of Tripura". The work also involved supply of materials required for the purpose. The petitioner purchased the materials in deferent States outside the State of Tripara or placed orders for supply of the same to Tripura for use in execution of the aforesaid contract. The terms of the contract stipulated movement of the goods from such other States to the State of Tripura. As the transactions in this case related to a period after the coming into force of the Constitution (46th Amendment )Act, 1982 which enables the States to levy tax on the transfer of property in goods involved in execution of works contract and incorporation of section 3A in the Tripura Sales Tax Act, 1976, hereinafter '-the Tripura Act", by the Tripura Sales Tax (3rd Amendment) Act, 1984 which provides for payment of tax on such transfers, there is no controvercy as to \vheilier the transfer of property in execution of the aforesaid contract amounts to sale or not. The undisputed position is that it amounts to sale and is exigible to tax. As the supplies of materials in the instant case for use in execution of the contract were all made from outside the State of Tripura, such supplies, according to the petitioner, amounted to inter State sales eligible to tax under the Central Act. There was no intra State sale in Tripura. The petitioner, therefore, did not register himself as a dealer under the sales tax Act in Tripura. It was, however, registered as a dealer under the Central Sales Tax Act, 1956, here­in after "the Central Act", in the State of West Bengal. It also filed its returns of turnover under the Central Act with the authorities under the said Act in West Bengal.

On 9th May, 1987, the petitioner firm received a notice of demand issued by the Superintendent of Taxes, Agartala under section 23 of the Tripura Sales Tax Act. An order of assessment was also annexed. From the order of assessment, it could be gathered that tax had been levied by the Superintendent of Taxes on the value of materials supplied by the petitioner to the Executive Engineer, Tripura from places outside the State of Tripura treating the same as "intra State sale in Tripura". It was done on the ground that the actual transfer of property in the materials used in the contract took place in the State of Tripura. In the said order of assessment, reference was also made to a notice under section 6(1) of the Tripura Sales Tax Act issued by the Superintendent of Taxes asking the petitioner firm to show cause as to why it should not be registered as a dealer under the said Act. The petitioner, however, denied the receipt of any such notice. As the Superin­tendent of Taxes was of the opinion that the supplies made by the petitioner during the period 3.7.86 to 11.2.87 amounting to Rs. 37,93,326.36 were intra State sales, he made the impugned assessment under section 11(2) of the Tripura Act.

The petitioner has challenged the aforesaid order of assessment made under section 11(1) of the Tripura Act on two grounds. The first ground is that the assessment is wholly illegal and without jurisdiction as it has been passed without initiating any proceeding for assessment under section 11(1) of the Tripura Sales Tax Act by service of a valid notice calling fora return which is a condition precedent for such initiation. The second conten­tion of the petitioner is that the assessment is not tenable even on facts, inas­much as there is no intra State sale involved in the transaction in question. The submission, in other words, is