JAGADISAN, J.

These tax revision cases and the writ petitions raise a common question of law, challenging the validity of the amendment to section 8-B(2) of the Madras General Sales Tax Act introduced by Madras Act 1 of 1957. It will be convenient to deal with this point first before setting out the facts of each case and considering the contentions turning upon them.

Section 8-B, as it stood before its amendment by Madras Act I of 1957, reads :-

"8-B. (1) No person who is not a registered dealer shall collect any amount by way of tax under this Act; nor shall a registered dealer make any such collection except in accordance with such conditions and restrictions, if any, as may be prescribed :

Provided that the State Government may exempt persons who are not registered dealers from the provisions of this sub-section until such date, not being later than the 1st day of April, 1948, as the State Government may direct.

(2) Every person who has collected or collects any amount by way of tax under this Act, on or after the 1st day of April, 1947, shall pay over to the State Government within such time and in such manner as may be prescribed, all amounts so collected by him if they are in excess of the tax, if any, paid by him for the period during which the collections were made."

The words in section 8-B(2)," and in default of such payment, the amounts may be recovered as if they were arrears of land revenue" *

, were deleted by section 7 of Madras Act 15 of 1956. In Tata Iron and Steel Co. Ltd. v. State of Madras , a Division Bench of this Court (Satyanarayana Rao and Rajagopalan, JJ.) held that what a registered dealer was empowered to collect from purchasers under section 8-B(1) of the Madras General Sales Tax Act was only what was lawfully leviable as tax and that a collection by a registered dealer from his purchasers under a mistaken conception of the liability of his transaction to be assessed under the Act was not liable to be paid over to the State Government as the collection was not a realisation by way of tax. At page 393, Rajagopalan, J., observed thus :

"What section 8-B(2) requires of every person is that he should pay over to the State Government 'all amounts so collected by him', that is, all amounts collected by way of tax. That, in the case of a registered dealer should apply only to what he could collect by way of tax within the meaning of section 8-B(1). In the case of the unregistered dealer, though he lacks the authority conferred on the registered dealer by section 8-B(1) to make any collections, the expression 'so collected by him' would only apply to the collection referred to in the earlier part of section 8-B(3), the collection of any amount 'by way of tax under this Act.' In both cases, the interpretation 'by way of tax lawfully leviable under this Act' would fit in with the obligations imposed by section 8-B(2) though we realise the anomalous position of an unregistered dealer on whom no rights were conferred but on whom only obligations were imposed." *

This decision opened the eyes of the State, and Madras Act I of 1957, which took effect from 1st April, 1957, was the result. Section 8-B(1) and the proviso was not in any way modified or amended by this later Act. Section 8-B(2) was re-enacted in the following terms :

"Every person who has collected or collects any amount purporting to be by way of tax under this Act, on or after the 1st day of April, 1947, whether or not any tax is due from him under this Act in respect of the transaction in which he has collected or collects such amount, shall pay over to the State Government within such time and in such manner as may be prescribed, all amounts so collected by him if they are in excess of the tax, if any, paid by him for the period during which the collections were made."The newly introduced words are" any amount purporting to be by way of tax", instead of the words (as they were prior to the amendment)" any amount by way of tax under this Act