Chandra Reddy, C.J.
1. The question raised in this tax revision case is whether the opinion offered by the Deputy Commissioner of Commercial Taxes, namely, that if an oil miller, who purchased ground nut and paid sales tax at the purchase point, subsequently crushes the same quantity in his mills into oil and effects sales, he gets rebate to the extent of tax payable to the oil millers and ghanawallas having more than one ghana, precludes the Government from levying tax on such oil.
2. The petitioner, Messrs. Venkateswara Oil Mills, Walker Town, Secunderabad, which deals in groundnuts and groundnut oil, was assessed to sales tax on its total turnover in the year 1953-54. Rebate was claimed by him in regard to oil which was manufactured out of groundnuts purchased by him and on which sales tax was paid at the purchase point, on the ground that such turnover was not eligible to tax. This turnover amounted to Rs. 2,21,010-8-6. The assessing authority rejected this claim, presumably, on the ground that there is no provision in the Hyderabad General Sales Tax Act (XIV of 1950) under which such relief could be claimed.
3. Aggrieved by the order of the Sales Tax Officer, the assessee took the matter in appeal to the Deputy Commissioner of Commercial Taxes. Before him, rebate was claimed inter alia on the basis of a letter written by the Deputy Commissioner on the 13th September, 1952, to M/s. Hyderabad Oil Mill Owners' Association.
4. Having regard to the importance of this document in the context of the present enquiry, it is convenient to extract it in extenso.
With reference to your letter cited above, I have to inform you that oil millers and ghanawallas (having more than one ghana) who happen, to purchase groundnut and pay sales tax at purchase point are eligible for a relief to the extent of sales tax payable on oil held by them.
To be clear, if a miller purchases one palla of groundnut and pays purchase tax and if he crushes the same quantity in his mills into oil and effects sales, he gets rebate to the extent of tax payable to oil millers and ghanawallas having more than one ghana.
Groundnut cake has been exempted as per Finance Department Notification No. 6 dated 24th January, 1951, and item No. 11 of Schedule I of the Hyderabad Sales Tax (Third Amendment) Act, 1952. The dealers of groundnut oil will have to pay sales tax at every sale.
5. This letter, no doubt, advises the Oil Mill Owners' Association that in transactions like the present one, the millers would be entitled to rebate. However, the contention based on this letter did not prevail with the Deputy Commissioner with the result that he dismissed the appeal.
6. The further appeal to the Sales Tax Appellate Tribunal also proved unsuccessful. Before the Tribunal, it was urged that, acting on that opinion, the assessee refrained from collecting the tax from the consumers and that, therefore, the Department was estopped from enforcing the tax liability of the assessee. This submission was rejected by the Tribunal in the view that the Deputy Commissioner acted without authority in directing such exemption and consequently there was no estoppel against the provisions of the statute. It is to revise this order of the Tribunal that the present revision has been filed.
7. We are now called upon to decide as to the effect of this letter upon the right of the Department to collect sales tax on commodities which are, admittedly, not exempt from payment of tax either under the statute itself or under any rule or notification issued thereunder. There is no provision in the statute which enables the Deputy Commissioner or even the Commissioner either to grant rebate or to offer advice to assessees on any matter. That being so, when the letter in question was written by the Deputy Commissioner he was not acting within the scope of his statutory authority. We are not told as to the circumstances under which it came to be written. It is also not explained as to what was the order which required any clarification or the provision of law which had to be correctly interpreted. Our attention was not drawn to any section of the enactment or any rule which was capable of yielding two constructions or capable of being misunderstood by the assessee and which necessitated the assessee to approach the Deputy Commissioner for clarification or advice.
8. That apart, even if it were a mistaken interpretation of any statutory provision by an officer of Government, it would not bind the Government and would not create an estoppel against the statute. Under the Hyderabad General Sales Tax Act, the department was entitled to impose taxes on the sale of goods, a right which could not be taken away by a wrong interpretation placed by a subordinate officer of the Government. If effect is to be given to the argument of the learned counsel for the petitioners, an officer of Government could defeat the very object of a legislation, passed by the State Legislature in exercise of the authority derived under item 54 of List II in the Seventh Schedule of the Constitution. This legislative measure was enacted with the object of providing additional source of revenue to the State. That being so, a subordinate department cannot do anything which will result in detriment to public treasury. The subordinate officials of Government cannot release a subject from an obligation to pay such a tax. The statute imposes a duty of a positive kind on a dealer to pay tax on his turnover. He cannot escape liability to pay that tax by setting up a release from that obligation by an officer of Government as the order having that effect is null and void.
9. In this connection, we may cite the judgment of the Privy Council in Maritime Electric Co. v. Dairies A.I.R. 1937 P.C. 114. In that case, a private company functioning as a public utility company in the City of Fredericton sold electric power to the respondent company carrying on dairy business in the same city. The appellant rendered to the respondents each month a statement purporting to show the amount of electric energy supplied to the latter purporting to be based on a reading of the meter placed by the appellants on the respondents' premises for the purpose of registering the energy so supplied. The respondents believed the statements and they paid the amounts to the appellants according to the statements. On the basis of these charges, the cost of manufacture of milk products was calculated and the amounts so fixed were paid to the farmers from whom they bought the cream. It was later on discovered that there was a mistake in rendering the statements showing incorrect amounts to be due.' Thereupon, the appellants claimed the difference between the amount due to them on correct computation in accordance with the schedules in force and the amounts already paid. The right of the appellants to recover the remaining balance was denied by the respondents. It was contended that the appellants were estopped from claiming it, as the respondents acted upon the said statements believing them to be true and paid more money than they would have paid if the amounts subsequently claimed had been rendered and claimed by the appellants earlier. The plea of estoppel was disallowed by the Privy Council.
10. After reviewing elaborately the case law on the subject, their Lordships inter alia observed as follows :.where as here the statute imposes a duty of a positive kind, not avoidable by the performance of any formality, for the doing of the very act which the plaintiff seeks to do, it is not open to the defendant to set up an estoppel to prevent it. This conclusion must follow from the circumstance that an estoppel is only a rule of evidence which under certain special circumstances can be invoked by a party to an action; it cannot therefore avail in such a case to release the plaintiff from an obligation to obey such a statute, nor can it enable the defendant to escape from a statutory obligation of such a kind on his part.
11. We may cite here Reg. v. Blenkinshop  1 Q.B. 43, the judgment of the Privy Council. There, a municipal body, under a mistake of law, sent demands to a railway company for only one-third of the sums legally due. The error continued for four successive years. In the fifth year, the concerned officers of the municipality took steps to recover the amounts unpaid. The railway company sought to resist the claim on the ground of estoppel pleading that the company had acted on the statements sent to them and paid out the money in dividends. But the plea of estoppel was overruled. In this connection, we may also usefully extract the following observations of Lord Watson in Anctil v. Manufacturers' Life Insurance Co.  A.C. 604:
The rule of the Code appears to them (i.e., their Lordships) to be one which rests upon general principles of public policy or expediency, and which cannot be defeated by the private convention of the parties.
12. In this case, the question was whether it was open to an insurance company to attack the policy on the ground of lack of insurable interest within the meaning of the civil Court of Lower Canada, in view of a condition in the policy of life insurance which provided for the policy becoming incontestable on any ground if the same had been in force for a year and if the premiums were promptly paid. This was answered in the affirmative.
13. The observations of Lord Atkin in In re A Bankruptcy Notice  2 Ch. 76 at 97 are to a like effect. He remarked : -
Whatever the principle may be (referring to a contention as regards approbation and reprobation), it appears to me that it does not apply to this case, for it seems to me well established that it is impossible in law for a person to allege any kind of principle which precludes him from alleging the invalidity of that which the statute has, on grounds of general public policy, enacted shall be invalid.
14. Following the Privy Council ruling in Maritime Electric Co. v. Dairies A.I.R. 1937 P.C. 114, a Bench of the Calcutta High Court in Hindustan Motors Ltd. v. Union of India A.I.R. 1954 Cal. 151, held that there could be no estoppel against the Sea Customs Act, 1878, in bar of the claim of the customs authorities. Similarly, in Secretary of State v. Faredoon A.I.R. 1934 Bom. 434, it was held that a mistaken interpretation made by Government officers of a grant by the Crown and their consequent mistaken acts would not be binding on the Crown and would not operate as estoppel as against the Crown. It is now well-settled that there could be no estoppel against a statute. Here, the Hyderabad General Sales Tax Act imposes a duty on every dealer to pay tax on the goods sold or purchased by him as required by the provisions of the Act. That being so, the dealer was under a liability to pay tax on his turnover and it was not competent for any official of the department to release any dealer from payment of such tax. Such a release will be null and void and cannot be relied upon by any dealer to evade payment of tax.
15. Under the Hyderabad General Sales Tax Act, no rule similar to Rule 18 of the Madras Turnover and Assessment Rules, 1939, which entitles a dealer to claim 'a deduction equal to the value of the groundnut and/or kernel purchased and converted by him into oil and cake provided that the amount for which the oil was sold was included in his turnover' was framed. We are, therefore, unable to understand the basis of the opinion of the Deputy Commissioner. The correspondence that has preceded this opinion has not been placed before us.
16. It is also worthy of note that the plea that the assessee, acting on the opinion of the Deputy Commissioner, refrained from collecting the tax from its customers, was put forward for the first time only before the Sales Tax Appellate Tribunal. As we have already pointed out, before the Sales Tax Officer this point was not raised.. Before the Deputy Commissioner, it was merely urged that (sic) relief mentioned above. It was not even alleged before the Deputy Commissioner that it was because of this opinion the petitioner did not collect sales tax on the oil sold by him. It was only before the Tribunal that this plea was put forward for the first time. It was not shown that the assessee had in fact acted to his detriment on the basis of this letter.
17. The decision of a Bench of this Court in China Sambamurty v. Additional Income-lax Officer, Vizag  2 An. W.R. 515, called in aid by Sri Ranganathachari, counsel for the petitioner, is irrelevant and docs not throw light on the question before us.
18. In the result, the tax revision case is dismissed, but without costs.