The main legal point established in the judgment is that the advance tax demanded under section 18A of the Income-tax Act is to be regarded as income-tax, and therefore, the penalty imposed under section 46(1) was valid.

( 1 ) WHETHER an assessee who commits default in the payment of the advance tax demanded under section 18a of the Income-tax Act can be made liable to pay a penalty under the provisions of section 46 (I) of the Act is the interesting question that arises in these two writ petitions.

( 2 ) THE material facts are these :

( 3 ) THE petitioner who had been previously assessed to income-tax was required under the provisions of section 18a of the Income-tax Act, to pay the advance tax for the assessment year 1955-56. On this committing default in the payment of such advance tax, the Income-tax Officer, under the provisions of section 46 (I) of the Act, imposed a penalty of Rs. 490 by an order made by him or May 23, 1955. On the assessee continuing to be in default, the Income-tax Officer made a second order on September 3, 1955, imposing a further penalty of Rs. 1,000 under the provisions of Section 46 (1a) of the Act.

( 4 ) THESE writ petitions are presented by the petitioner for certiorari to bring up and quash those orders made by the Income-tax Officer. Writ Petition No. 3 of 1957 is directed against the order made on May 23, 1955, while Writ Petition No. 4 of 1957 is directed against the order made of september 3, 1955.

( 5 ) THE contention of the petitioner in these writ petitions is that the Income-tax Officer had no authority to imposed any penalty on the petitioner in respect of the default committed by him in the payment of the advance tax required to be paid under section 18a of the Act. The contention is that advance tax is not Income-tax and so the default committed by him in the payment of advance tax is not a default committed by him in making a payment of Income-tax and unless the assessee commits default in the payment of Income-tax, the provisions of section 46 (I) of the Act are not attracted.

( 6 ) MR. Srinivasan, the learned a advocate for the petitioner, has contended before us that it is only the tax determined after an assessment is made under section 23 of the Act, at rates prescribed by the relevant Finance Act, that can be called Income-tax. The tax required to be paid under the provisions of section 18a, not being a tax determined by an assessment under section 23 of the Act, is not, he urges, income-tax. So, the default committed by the petitioner in this case did not entail the imposition of any penalty under the provisions of section 46 (1) of the income-tax Act.

( 7 ) MR. Srinivasan has also contended that Income-tax is the tax that is charged on the income of a person of the previous year and the advance tax being really a tax on the income of the year in which the advance tax is demanded, such advance tax cannot be regarded as income-tax. Mr. Srinivasan also contends that, in any event, the provisions of section 46 (1) of the Income-tax Act are unconstitutional for the reason that an assessee in default is subject not only to a penalty under the provisions of section 46 (1) of the Act but is also required by section 18a (8) of the Act to pay interest on the amount not paid by him.

( 8 ) IF Mr. Srinivasan's contention is right that the advance tax required to be paid under section 18a if the Act is not Income-tax, the orders of the Income-tax Officer are liable to be quashed. The question, therefore, is whether the advance tax which the assessee in this case was required to pay under the provisions of section 18a of the Act can be regarded as income-tax for the omission to pay which the Income-tax Officer may imposed a penalty under section 46 (1) of the act.

( 9 ) IN support of his contention that advance tax is not income-tax. Mr. Srinivasan has strongly relied on sub-section (1) of section 18a of the Act in which the advance tax that could be demanded of an assessee is not described as income-tax but is referred to only as an amount equal to one-quarter of the Income-tax and super-tax payable on so much of the assessee as is included in his total income of the latest previ