BIMAL CHANDRA BASAK, J. ( 1 ) THIS appeal and the writ petition, in which an interim was made by the Trial Court and which is the subject matter of this appeal, are now before us. ( 2 ) THE facts of this case are shortly as follows:- According to the writ petitioners, they placed an order for import of cold formed section from sheets galvanised corrugate from a foreign seller. According to the petitioners, they opened a Letter of Credit for import on 11th January, 1983 and on 11th March 1983 the foreign supplier despatched 1004. 710 M. T. of the materials per S. S. Jaltarang. This entire transaction was entered into on the basis of the existing duty. The dispute is regarding the auxiliary duty. Admittedly, at the time of shipment of the materials on 11th March 1983 it was 20% ad valorem. By notification dated 18th March 1983 it was increased from 20% to 25%. Admittedly, the bill of entry was submitted and the ship arrived subsequently. On the 20th May, 1983, that is before the arrival of the ship the petitioners filed this writ petition praying for:-" (a) A writ of and/or order and/or direction in the nature of Mandamus commanding the respondents to allow the clearance of the goods imported by the petitioner in respect of the goods covered by the documents and/or statement included in Annexure "a" hereto upon by levying basic duty of 15% ad valorem auxiliary duty only at the rate of 20% ad valorem and countervailing duty at the rate of Rs. 850/- per metric tones; (b) A writ of and/or an order and/or a direction in the nature of Mandamus commanding the respondents their servants and agents from allowing clearance of the goods imported by the petitioner covered by the documents and/or statements included in Annexure "a" hereto upon payment under open General Licence; (c) An appropriate writ order or directions declaring the forms of bills of entry prescribed under Rule 3 of the Bill of Entry (forms) regulations 1976 in so far as it prescribed for including landing charges in the assessable value of goods for the purpose of levying duty of customs as ultra vires and unconstitutional; (d) A writ order or direction in the nature of Mandamus calling for the records of the respondent No. 1 and quashing the impugned decisions of the Central Government as contained in the minutes of the meeting of the Advisory Council dated 10th of July 1975 in regard to the landing charges; (e) A writ of and/or order and/or directions in the nature of certiorari commanding the respondents to transmit and certify the records relating to the said purported demands of auxiliary duty in excess of 20% and countervailing duty in excess of Rs. 850/- per M. T. and the claim for Customs Duty in the assessable value by adding thereof the landing charges, freight, packing and insurance charge in the assessable value of the said goods mentioned in Annexure "a" hereto and all purported proceedings relating thereto so that the same may be set aside and/or quashed and conscionable justice might be rendered; (f) A writ of and/or order and/or direction in the nature prohibition commanding the respondents to forbear from levying and/or demanding basic duty of 15% ad valorem auxiliary duty in excess of 20% and countervailing duty at the rates exceeding Rs. 850/- per metric ton in respect of the goods covered by the said contract and/or other documents included in Annexure "a" hereto and or from in any way applying the said notification dated 1st March 1983 in respect of the said imports or to include the freight insurance packing and lending charges in determining the assessable value of the said goods. " ( 3 ) UPON such application a Rule was issued and an interim order was passed on the 20th May 1983 to the following extent:-"there will be a rule as prayed for Returnable eight weeks hence. There will be an interim order to the following effect. Upon the undertaking to Court by Mr. N. P. Agarwalla of M/s. L. P. Agarwalla and Co. , Advocate-on-record of the petitioner that a Bank Guarantee for the entire disputed amount to the satisfaction of the Collector of Customs, Calcutta, will be furnished within a week from date, there will be an order upon the Customs authorities to release the goods in terms of prayer (J) to the petition which are the subject matter of the application subject to compliance by the petitioner with the other customs formalities. The Bank Guarantee will be in favour of the Collector of Customs, Calcutta. The Bank Guarantee will be of Canara Bank, a nationalised Bank having its office in Calcutta and the Collector of Customs is directed to accept the form as issued by the above mentioned bank. This order will not stand in the way of the Customs authorities making their assessment without prejudice to the rights and contentions of the petitioner. But the Customs Authorities will not take any steps to enforce the same until further orders of this Court. This interim order is being passed ex parte as I am satisfied that otherwise the petitioner would suffer extreme hardship. Let the grounds and a gist of my order made today be served on all the respondents by the 1st June, 1983. Let this matter appear as an application in Chambers on the 2nd June 1983. " ( 4 ) BEING aggrieved by the same, this appeal was preferred by the Collector of Customs. ( 5 ) BY an order dated 21st June 1983 the interim order was modified by the Appeal Court and the writ petitioners were directed to put in 25% of the disputed amount in cash and 75% in bank guarantee. This matter came up before us on the 17th September, 1987 and in order to expedite the matter we directed the hearing of the writ petition itself and gave direction for filing of affidavit-in-opposition and affidavit-in-reply. Such opposition and reply have been filed and this matter has come up today for hearing. This matter came up before us on the 17th September, 1987 and in order to expedite the matter we directed the hearing of the writ petition itself and gave direction for filing of affidavit-in-opposition and affidavit-in-reply. Such opposition and reply have been filed and this matter has come up today for hearing. ( 6 ) NOBODY appeared on behalf of the writ petitioners. We have heard the Revenue Authority. In our opinion there is no merit in this writ petition. The change in rate was made prior to importation. Whether the agreement was entered into on the basis of rate prevailing at the time of agreement is immaterial. It is the "customs" "duty" that is, a duty on importation. Therefore, the date of importation is important and not the date of agreement pursuant to which such importation is made. Therefore, the date of importation is the relevant date for ascertaining the duty to be paid. Admittedly on the date of importation, new increased duty has came into force in the present case. Therefore, the writ petitioners are bound to pay duty at the increased rate. ( 7 ) THERE is no question of equitable estoppel herein. The duty is on importation. Merely because on the basis of the existing rate an agreement is entered into and between the date of agreement and the date of importation the rate of duty is changed, this is no ground for applicability of the principle of equitable estoppel. In the case of Revenue no such principle can be applied on such basis. ( 8 ) THERE is no question of any representation by the Revenue and there cannot be any question of any one acting on the basis of such representation to its detriment. There is no merit in this writ petition. Accordingly, the appeal is allowed. The interim order passed is set aside. All interim orders are vacated the writ petition is dismissed and Rule discharged. There is no merit in this writ petition. Accordingly, the appeal is allowed. The interim order passed is set aside. All interim orders are vacated the writ petition is dismissed and Rule discharged. ( 9 ) SO far as the bank guarantee furnished is concerned, the Customs Authority shall be entitled to encash the same immediately pursuant to the direction of the Trial Court dated 20th May 1983 as modified by the Appeal Court's order dated 21st June 1983, so far as the assessment proceedings are concerned, a further opportunity will be given to file reply within a fortnight from the date of such notice and the assessment proceedings are to be completed within two months from this date. ( 10 ) BEFORE we conclude we may point out one thing. This appeal was preferred by the Customs Authority in June 1983. No step was taken by them for early hearing of this matter for more than 4 years. This appeal came up before us only on the usual course. We directed the Customs Authority to affirm an affidavit showing the present position and the position subsequent to the order appealed from dated 20th May 1983. Pursuant to the direction an affidavit has been affirmed by one Gopalaswamy Sampath on 25th January 1988 from which it appears that the events after the order appealed from was passed on the 20th May 1983 and after the Appeal Court's order modifying the Trial Court's order dated 21st June 1983 are as follows:"5. Thereafter pursuant to the liberty given by the Hon'ble Appeal Court, the Customs Authorities on or about 24th June, 1983 assessed duty in respect of the goods which are subject matter of the writ petition and the total amount of admitted duty amounted to Rs. 22,76,947. 76p. and 25% of the total dispute duty amounted to Rs. 2,69,590. 94p, as will appear from a chart annexed herewith and marked. ""6. After the assessment was completed the Assistant Collector of Customs issued a show cause notice, to the writ petitioner on 25th June, 1983. Thereafter, the said writ petitioner filed another writ petition in the Appellate Side of this Hon'ble Court challenging the said Notice being CO. No. 9557 (W) of 1983 whereupon an expiry order was made by the Hon'ble Mr. Thereafter, the said writ petitioner filed another writ petition in the Appellate Side of this Hon'ble Court challenging the said Notice being CO. No. 9557 (W) of 1983 whereupon an expiry order was made by the Hon'ble Mr. Justice B. C. Roy on 4th October, 1983 restraining the respondents from proceeding any further with the show cause notice issued by the Asstt. Collector of Customs for Appraisement Group III dated 25th June, 1983. A xerox copy of the Minute of the said order is annexed herewith and marked "d". "7. After being served with a copy of the said writ petition and the said ex-parte interim order, the respondents appeared and opposed the said application and for extention of interim order. By an order dated 27th February, 1984, the Hon'ble Mr. Justice B. C. Roy was pleased to modify the interim order dated 4th October, 1983 to the extent that the petitioner will show cause pursuant to the show cause notice to the authorities concerned but the authorities concerned shall not proceed further pursuant to the submission of the show cause reply until further orders of Court. A xerox copy of the Minute of the said order is annexed herewith and marked "e". "8. Inspite of the said order of the Hon'ble Court dated 27th February, 1984 the said writ petitioner Shree Hanuman Steel Traders has not yet replied to the show cause notice and as such, no steps could be taken by the Assistant Collector of Customs. A copy of the said show cause notice is annexed herewith and marked "f". " ( 11 ) WE cannot accept such explanation for such inaction though we are surprised to find that inspite of the order dated 26th February 1984 the writ petitioners did not file any reply. No step has been taken by the Customs Authority. The order of 20th May 1983 read with the order of 21st June 1983 powers the Customs Authority for making assessment. There are merely not to take any step to enforce the same. In the second proceeding, that is, CO. No. 9557 (W) of 1983 the petitioners were directed to show cause but it was directed that the Authority concerned shall not proceed further until further order of this Court. There are merely not to take any step to enforce the same. In the second proceeding, that is, CO. No. 9557 (W) of 1983 the petitioners were directed to show cause but it was directed that the Authority concerned shall not proceed further until further order of this Court. If the petitioners did not file any such reply the Customs Authority should have approached this Court for further orders, in the second proceedings, particularly having regard to the order passed in the first proceeding. They could have also approached the Appeal Court in the first proceeding. But they have chosen not to follow either of the same, but they have maintained a total silence. The persons incharge of conduct of litigation in this case on behalf of the Customs Authority are guilty of gross delay and negligence. We strongly condemn the same particularly having regard to the fact that it has become the habit in some quarters to blame the Court for delay in proceedings where as we have found in most of the cases that the persons who are incharge of the conduct of litigation on behalf of the Revenue Authorities are to be blamed. We condemn this attitude.