JUDGMENT CHANDURKAR J. - This appeal filed by the plaintiff-Society arises out of a suit filed by them claiming refund of a sum of Rs. 1,36,142 which is alleged to have been illegally recovered by the defendants as sales tax on either the sugar plant, which the defendants had agreed to install, or the separate components of the said sugar plant. 2. The plaintiffs are manufacturers of sugar plants and an agreement was entered into between the plaintiff society and the defendant company on 2nd September 1963 for the purchase and sale by the defendants of machinery and equipment for a cane sugar factory of 1000 tons capacity per day of 22 working hours and cap3ble of being extended to 1250/1500 tons capacity by suitable additions. The details of the machinery and equipment which were agreed to be supplied were specified in Schedule A to the agreement and compendiously they have been referred to as "the sugar plant". The contract price of the sugar plant was agreed to be Rs. 84,00,000 F.O.R. place of manufacture or place of despatch in ,case of-ready components. The price agreed was exclusive of all sales taxes, octroi, excise duty, local taxes or other levies as well as all freight charges, insurance, customs duty and clearing charges on imported components and goods, all of which were 'for purchasers account'. In case there was any addition or modification to the specifications in Schedule A, the price was subject to alteration. The agreement defined the term "contract price" to mean "the price quoted above in this clause together with all increases or decreases thereto under this agreement". The special provision with regard to sales tax and other taxes was made in clause 2 (c) of the agreement. Material parts of this clause are as follows:- "The contract price is exclusive of all sales taxes, octroi, local taxes and other levies which may be payable in respect of any of the goods covered by this agreement and all such taxes, etc. will be for Purchasers' account. The amount of sales tax on the goods will be shown separately in each invoice. will be for Purchasers' account. The amount of sales tax on the goods will be shown separately in each invoice. Should the amount of Sales tax collected by sellers from purchasers be too low and, should the appropriate authority be successful in claiming an additional amount of tax from the sellers or should any new tax or levy be imposed by the Central or State Government or by any local Indian Authority such additional charges shall be paid by the Purchaser. The sellers agree to help the purchasers to obtain refund of duty and taxes found to have been paid in excess." 3. The agreement provided for terms of payment at certain percentage of the contract price to be paid at stated intervals. With regard to the delivery of the goods, it was provided in clause 4 of the agreement that the machinery or goods shall be despatched as and when ready by rail to Bhigwan railway station (C. R.) (Name of the nearest railway station) or by road to the purchasers' factory site from Poona or from the places specified in paragraph (b) and the relative documents shall be negotiated by sellers and payment obtained by them in Bombay against the letter of credit which the purchasers bank was required to establish. All freight payable in respect of such despatch was to be for purchasers account. Sub-clause (c) of clause 4 of the agreement, on which great stress was laid on behalf of the plaintiffs, ran as follows :- "Notwithstanding the provisions of the foregoing sub- paragraphs, the property and risks in all goods sold in pursuance of this agreement shall pass to the Purchasers immediately upon such goods being handed over to the carriers for onward despatch to the Purchasers." 4. The agreement also made some provision with regard to supervision of the erection of the plant and since some arguments were advanced on behalf of the appellant based on the terms relating to erection of the plant, it is necessary briefly to refer to those provisions in the agreement. Clause 6 of the agreement is headed as "Erection Supervision". The agreement also made some provision with regard to supervision of the erection of the plant and since some arguments were advanced on behalf of the appellant based on the terms relating to erection of the plant, it is necessary briefly to refer to those provisions in the agreement. Clause 6 of the agreement is headed as "Erection Supervision". Clause (a) thereof reads as follows:- "The sellers undertake to provide the purchasers with the services of one Chief Erector and as many Assistants as the Sellers consider necessary to supervise the Erection of the plant to enable the Purchasers to complete Election by January 1965 and to assist and advise purchasers in putting the plant into mechanical operation ..”. The sellers, that is, the defendants, were under the agreement to deliver to the purchasers, that is, the plaintiffs, a schedule for delivery of erection work which, if adhered to, would enable the completion of erection and putting into operation the sugar factory by January 1965. The time schedule was to be delivered within six months from the date of receipt of advance payment. The material required for the erection of the plant such as tools and stores was to be made available by the purchasers who were also required to have a workshop installed and to have the structures of the factory building erected and roofed within a certain stipulated period. The defendants were entitled to reject any workman or engineers who were to be made available by the purchasers. The agreement also provided for payment of erection supervision costs and sub-clause (e) of clause 6 provided that in consideration of the services rendered by the sellers regarding erection supervision the purchasers would pay to the sellers a lump sum amount of Rs. 2,00,000 or the actual expenditure incurred by the sellers on erection supervision whichever was less. The agreement contained a guarantee clause whereby the sellers had guaranteed the proper performance of the machinery and the equipment. 5. Now, admittedly the defendants supplied the plant and machinery and for the purposes of the plant and machinery, some of the components required were secured from outside the State of Maharashtra. It is the plaintiff's case that in pursuance of the agreement, the defendants supplied to the plaintiffs ready components worth Rs. 5. Now, admittedly the defendants supplied the plant and machinery and for the purposes of the plant and machinery, some of the components required were secured from outside the State of Maharashtra. It is the plaintiff's case that in pursuance of the agreement, the defendants supplied to the plaintiffs ready components worth Rs. 27,22,840.27 from various places outside the State of Maharashtra, as detailed in Annexure A to the plaint, and on these Sales, the defendants charged and recovered an amount of Rs. 1,36,142 by way of sales tax purporting to recover the same under the provisions of the Bombay Sales Tax Act, 1959. The schedule to the plaint gives the details of the bills submitted by the defendants to the plaintiffs in respect of the various items showing the total amount of the bill and the total amount of sales tax at 5% charged by the defendants, 6. According to the plaintiffs, the goods mentioned in the Schedule to the plaint were supplied by the defendants to the plaintiffs and sold to them outside the State of Maharashtra and in different States and the property and the ownership in the said goods, according to the agreement, was to pass and did in fact pass to the plaintiffs at the respective places of despatch immediately upon such goods being handed over to the carriers for onward despatch to the purchasers, that is, the plaintiffs. In respect of those goods, according to the plaintiffs, liability to pay sales tax arose at the respective, places of despatch outside the State of Maharashtra and within the respective· States in whose territories the respective places of despatch were situated and not within the State of Maharashtra. Therefore, according to the plaintiffs, the defendants were not entitled to recover from the plaintiffs the amount of sales tax in accordance with the provisions of and at the rates specified in the Bombay Sales Tax Act, 1959. Such recovery of sales by the defendants is, therefore, illegal and unauthorised, according to the plaintiffs, the period during which these recoveries have been made is, according to the plaintiffs, from 24th April 1964 to 30th June 1965. These payments, according" to the plaintiffs, were made by mistake of law or under a mistaken notion of the law entertained at the time of making the respective payments. Alternative case pleaded is that the sales tax was paid under coercion. These payments, according" to the plaintiffs, were made by mistake of law or under a mistaken notion of the law entertained at the time of making the respective payments. Alternative case pleaded is that the sales tax was paid under coercion. The plaintiffs, therefore, claimed that they were entitled to ask for a refund of the said amount of Rs. 1,36,142 under the provisions of section 72 of the Contract Act. 7. For the purposes of limitation, it is stated by the plaintiffs that a doubt with regard to the legality of the recovery of sales tax by the defendant was created in the plaintiffs' mind for the first time on 28th July 1964 and' they received legal advice from sales tax experts on or about 11th October 1965 that they were not legally liable to pay sales tax under the Bombay Sales Tax Act and the plaintiffs thus found out their mistake on or about 11th October 1965. Thus a claim for Rs. 1,36,142 with future interest at the rate of 6% p. a. from the date of the suit was made in the plaint. The plaint was filed on 25th July 1967. 8. In the written statement, the defendants denied that sales tax was· illegally recovered. According to them, the Civil Court has no jurisdiction to entertain and try the suit in view of the provisions of section 54 of the Bombay Sales Tax .Act. Further, according to the defendants, the agreement was to supply a sugar plant as a whole and there was no privity of contract between the plaintiffs and the defendant to sell any component parts and sales tax collected was in respect of the whole unit of the plant. The defendants' case was that they found it convenient to entrust the supply of certain ancillary parts to sub-contractors and the sub-contractors who had supplied the goods from outside the State were not in any way concerned with the plaintiffs. The sub-contractors had sent the railway receipt in the name of self or in the name of the defendant company. The invoices were also sent to the defendants who paid off their bills and the defendants negotiated the railway receipts in favour of the plaintiffs through the bankers. The sub-contractors had sent the railway receipt in the name of self or in the name of the defendant company. The invoices were also sent to the defendants who paid off their bills and the defendants negotiated the railway receipts in favour of the plaintiffs through the bankers. Thus, according to the defendants, as regards the supply of material from the sub-contractors, orders were placed by the defendants, advance payments were also made by them and documents were also retired by them against payment, duly paying the cost of the mater altogether with sales tax payable on inter· State scales. They have also taken a plea that the amount of tax collected has already been paid by the defendants to the Sales Tax Authorities after it was assessed by them. 9. The evidence in the suit before the trial Court consisted mainly of the several invoices, bills and correspondence between the defendants and persons or firms who had sent goods from outside in respect of which the railway receipts were drawn either in their own names as self or in the name of the defendants. The only material oral evidence in the suit was of one Vasant, P. W. 1, who was the Managing Director of the plaintiff Society. 10. The trial Court took the view that there was no privity of contract between the plaintiffs and the traders outside the State of Maharashtra. The plaintiffs did not know the price of the component parts settled between the defendants and the traders and that the plaintiffs were not to worry and did not worry about the prices of these components because they were to get the sugar plant as one unit for the fixed price exclusive of taxes. With regard to the maintainability of the suit, the trial Court took the view that the sales tax was recovered from the defendants and paid to the Government and in the absence of the Government being a party, no decision with regard to the legality or otherwise of the recovery of sales tax by the defendants could· be taken behind back of the Government. The trial Court also found that as per agreement between the parties, the purchasers were liable to pay sales tax to the sellers who were to collect it and were to pay to the Government and who bad paid it in this case. The trial Court also found that as per agreement between the parties, the purchasers were liable to pay sales tax to the sellers who were to collect it and were to pay to the Government and who bad paid it in this case. The trial Court held that the plaintiffs bad failed to prove that the recovery of sales tax was unauthorised and illegal and further that the Civil Court had no jurisdiction to, entertain the suit in view of section 54 of the Bombay Sales tax Act. F0r the purposes of limitation, the trial Court held that a part of the claim for the period between 24th April 1964 to 25th July 1964 was time barred. Having found that the defendants were not liable to pay anything to the plaintiffs, the trial Court dismissed the plaintiffs' suit with costs. 11. The plaintiffs have now filed this appeal challenging the dismissal of their suit. 12. At the outset, we may notice a contention raised in the course of the arguments "on behalf of the appellants by Mr. Dalvi that there was nothing on record to show that the sales tax recovered by the defendants from the plaintiffs has in fad been paid to the Government. 13. It is difficult to see how the plaintiffs can be permitted to urge this contention. It is not their casein the plaint that the amount of sales tax recovered from the plaintiffs has been retained by the defendants. It is not even averred in the plaint that the amount of sales tax has not been paid by the defendants to the Government. The entire suit has proceeded on the footing that the sales tax amount recovered from the plaintiff.; has been paid by the defendants to the Government and the fact that the defendants have paid the amount of sales tax to the Government stands admitted by the plaintiffs in a letter written by them to the defendants (Ex. 579) dated 18th October 1965. By this letter, after having obtained the opinion of a sales tax consultant, Shri ShantiIal Shah, who is examined as a witness as P. W. 2 by the plaintiffs, the plaintiffs have asked the defendants to obtain a refund of sales tax from the State Government. 579) dated 18th October 1965. By this letter, after having obtained the opinion of a sales tax consultant, Shri ShantiIal Shah, who is examined as a witness as P. W. 2 by the plaintiffs, the plaintiffs have asked the defendants to obtain a refund of sales tax from the State Government. Paragraph 2 of this letter reads as follows:- "We now request you to proceed in the matter for obtaining refund of State Sales Tax charged and paid by you in the Government Treasury in respect 'of the machinery purchased outside Maharashtra State, as already promised by you," This letter, therefore, unequivocally admits that the defendants have paid the sales tax amount to the State Government. It is now too late for the plaintiffs to urge that the defendants have not paid the amount of sales tax to the State Government. 14. Mr. Dalvi on behalf of the plaintiffs has challenged the finding recorded by the trial Court that the suit is barred by section 54 of the Bombay Sales Tax Act. 15. Section 54 of the Bombay Sales Tax Act reads as follows: - "Save as is provided by section 61, no assessment made and no order passed under this Act or the rules made thereunder by the Commissioner or any officer or person subordinate to him shall be called in question in any Court, and save as is provided by sections 55 and 57 no appeal or application for revision shall lie against any such assessment or order," Mr. Dalvi has contended that the plaintiffs in the suit have not made any averments challenging any orders of assessment made against the defendants and assuming that the defendants have paid the amount of the tax, the limited contention of the plaintiffs, according to the learned counsel, was that the defendants were not entitled to recover any tax from the plaintiffs. The defendants have filed in the suit the photostat copies of the assessment orders for the period 1st April 1964 to 31st March 1965 (Ex. 590 collectively), which show that the total sales taxable were of the tune of Rs. 1,03,27,418. 16. The defendants have filed in the suit the photostat copies of the assessment orders for the period 1st April 1964 to 31st March 1965 (Ex. 590 collectively), which show that the total sales taxable were of the tune of Rs. 1,03,27,418. 16. Now, we must proceed on the footing that the sales tax recovered 'by the defendants from the plaintiffs has been credited by the defendants with the Government and that the defendants have been assessed to sales tax in respect of the sale for which, according to the plaintiffs, sales tax has been illegally recovered. Section 54 creates a bar of jurisdiction of any Court to go into the question of the legality or otherwise of an assessment made under the Sales Tax Act. The object of section 54 is clear. The object is that the assessment made under the Sales Tax Act can be subjected to scrutiny only by the authorities and the Tribunals created under the Act and by a reference made to the High Court by the Tribunal under section 61. The words of section 54 are; no assessment made and no order passed under this Act or the rules made thereunder .... shall be called in question in any Court ... ... to. These words are of the widest amplitude and they rule out any challenge to legality of assessment of sales tax in any Court whatsoever. 17. Now, apparently the argument that the plaintiffs are not calling in question any assessment order passed by any authority under the Sales Tax Act appears to be simple and plausible, but on a closer scrutiny, the argument is clearly unacceptable. The words shall be called in question do not necessarily mean that the challenge must be made directly to an assessment order. It is important to remember that section 54 does not make: any reference to an assessee and it cannot be, therefore, construed as referring merely to an assessee, as is contended on behalf of the appellants. The provision is one of general application. The effect of that provision is that the question as to whether any particular sales have been properly assessed or not or whether any sales have been legally assessed to sales tax or not is completely taken out of the purview of any Court and such questions are determinable only by the authorities and in the manner prescribed under the Act. It is difficult to see why the averments in the plaint do not amount to calling an assessment in question. Admittedly the defendants have been assessed to sales tax. In accordance with that assessment, sales tax has been paid by the defendants. Now, the contention of the plaintiffs that sales tax has been illegally recovered from the plaintiffs, if accepted, is bound to affect the assessment made by the Sales Tax authorities in the sense that what has been accepted by the defendants as legal assessment and what has been made as legal assessment by the Sales Tax Officers is being now asked to be adjudicated upon as an illegal assessment. The question as to whether particular sales are taxable under the Sales Tax Act or not is a matter within the exclusive jurisdiction of the Sales Tax authorities. Merely because the liability to sales tax of particular sales is being disputed not by the dealer but by the purchaser is no ground for. holding that the assessment is not being called in question. As a matter of fact, the Bombay Sales Tax Act does not make any express provision for passing on the burden of sales tax to the purchaser. Where a purchaser pays sales tax as demanded by the seller, the payment must be clearly referred to an agreement between the parties which may be either express or implied to pay sales tax charged by the Government. 18. So far as the present case is concerned, the agreement positively referred to the liability of the plaintiffs to pay sales tax. We have reproduced earlier clause 2 (c) of the agreement. Under that clause it is expressly provided that whatever sales tax may be payable" in respect of any of the goods covered by the agreement will be for purchaser's account, and the amount of sales tax will be shown separately in each invoice. There was, therefore, an express agreement between the plaintiffs and the defen4ants that whatever sales tax would be payable by the defendants would be paid by the plaintiffs. The liability to pay the sales tax by the defendants now stands expressly finally determined by the assessment orders. There was, therefore, an express agreement between the plaintiffs and the defen4ants that whatever sales tax would be payable by the defendants would be paid by the plaintiffs. The liability to pay the sales tax by the defendants now stands expressly finally determined by the assessment orders. If the defendants have been required to pay sales tax and their liability has been correctly assessed by the assessment orders, the plaintiffs under the terms of the agreement were bound to pay that sales tax because that amount of sales tax had become payable as contemplated by the agreement. Thus apart from the provisions of section 54 of the Bombay Sales Tax Act, the plaintiffs having agreed to pay sales tax which may be payable cannot now contend that the recovery of sales tax was illegal. Such a contention has a direct impact on the validity of the assessment orders and, in our view, even section 54 will bar such a claim. 19. As pointed out by the trial Court, there is another difficulty in the way of the plaintiffs. The trial Court bas held that the Government is a necessary party. Nothing has been urged before us to show as to why that finding of the trial Court was incorrect. Once an assessment under the Sales Tax Act has been made and moneys have been paid by the defendants to the State Government, whether the assessments Were properly made or not is a matter in which the State Government would be vitally interested. The determination of the question as to whether certain goods· were liable to sales tax or not cannot be made behind the back of the Government who is entitled to justify that certain goods were liable to sales tax because the sales tax is primarily payable to the Government and has in fact been paid in this case. 20. The learned counsel appearing on behalf of the defendants has invited our attention to the decision of the Supreme Court in Kamla Mills v. Bombay State1. In that decision the provision corresponding to section 54 of the 1959 Act was section 20 in the 1946 Sales Tax Act which read as follows :- "20. 20. The learned counsel appearing on behalf of the defendants has invited our attention to the decision of the Supreme Court in Kamla Mills v. Bombay State1. In that decision the provision corresponding to section 54 of the 1959 Act was section 20 in the 1946 Sales Tax Act which read as follows :- "20. Save as is provided in section 23, no assessment made and no order passed under this Act or the rules made thereunder by the Commissioner or any person appointed under section 3 to assist him shall be called into question in any Civil Court, and save as is provided in sections 21 and 22, no appeal or application for revision shall lie against any such assessment or order." The only material difference between section 20 of the Bombay Sales Tax Act, 1946, and section 54 of the Bombay Sales Tax Act, 1959 is that while the bar under section 20 of the Bombay Sales Tax Act, 1946, was in respect of the jurisdiction of the Civil Court, the bar under the new provision is created in respect of the jurisdiction of every Court. In Kamla Mills case no doubt, the suit was filed by a dealer who contended that a certain amount of sales tax was recovered by the State illegally and the illegality of the impugned assessment, levy, imposition and collection was discovered by it soon after the decision of the Supreme Court in Bengal Immunity Co. Ltd. v. State of Bihar2. One of the defences to the suit taken by the State was that the suit was barred under section 20. Dealing with the question as to whether the suit was barred under section 20, the Supreme Court held that even though an order of assessment was erroneous and it is based on an incorrect finding of fact, that could not be called in question in any - Civil Court. In paragraph 14, it was observed: "Section 20 protects assessment made under the Act or the rules made thereunder" by appropriate authorities. There can be little doubt that the clause "an assessment made" cannot mean the assessment properly or correctly made. The said clause takes. In all assessments made or purported to have been made under the Act. In paragraph 14, it was observed: "Section 20 protects assessment made under the Act or the rules made thereunder" by appropriate authorities. There can be little doubt that the clause "an assessment made" cannot mean the assessment properly or correctly made. The said clause takes. In all assessments made or purported to have been made under the Act. In its plaint, the appellant is undoubtedly calling into question the assessment order made against it, and such a challenge to the assessment order is plainly prohibited by section 20. An order of assessment, though erroneous, and though based on an incorrect finding of fact, is, nevertheless, an order of assessment within the meaning of section 20; and section 20, in terms, provides that it will not be called in question in any civil Court." 21. As already pointed out, it is no doubt true, as contended by Mr. Dalvi, that the suit in Kamla Mills case was filed by the dealer himself and, therefore, according' to Mr. Dalvi, the ratio of that decision will not be attracted in the instant case. The fact, however, remains that the averments in the plaint directly call into question assessment of sales tax which the defendants have been held liable to pay. Having regard to the wide amplitude of the words used in section 54, the question as to who challenges the assessment would not become very relevant. 'If the effect of the decision in the suit is that an assessment duly made by the authorities under the Sales Tax Act is held to be illegal, then it will still amount to calling the assessment in question arid even' though it is the purchaser who has asked for a refund of the amount of sales tax from the dealer on the ground that no sales tax was payable by the plaintiffs, such a claim will still be within the prohibition of section 54 of the Sales Tax Act. Appeal dismissed.