The doctrine of unjust enrichment applies to refunds, distinguishing between interim deposits and actual duty payments.

1. The appellant Company herein had imported a Steam Tube Dryer machinery / plant. Some dispute about the classification of the said machinery arose. The Revenue / Customs Authorities wanted the appellant to pay higher duty which the appellant was disputing. Insofar as the Custom Authorities are concerned, they had passed the orders calling upon the appellant to pay the duty. Without paying this duty, the appellant approached the High Court of Gujarat by way of writ petition with the prayer that the appellant be allowed to get the said machinery released on payment of admitted amount of duty.

2. On this writ petition, interim orders dated 4-5-1992 were passed permitting the appellant to deposit a sum of Rs.70 lakhs as a condition for utilising the machinery. We may record here that the appellant had earlier furnished the bank guarantee in the sum of Rs.1,45,27,079. The exact order which was passed on that date reads as under:
"At the same time, it will also be proper if the petitioner is directed to deposit some amount so that such money becomes available to the public exchequer. In our opinion, it will be quite fair and just if the applicant is directed to deposit Rs.70,00,000 in this Court as a condition for utilising the machinery. As it will take some time for the applicant to install the machinery and commission it, we direct the applicant to start paying Rs.70,00,000 from 1-8-1992, in four equal monthly instalments. The bank guarantee, which the applicant is required to continue, will have to be reduced to the extent instalments are paid by the applicant. The respondents will be at liberty to withdraw the amount that may be deposited by the applicant in this Court on condition that whenever called upon to do so; they will repay that amount within the time that may be specified by this Court."

3. As per the aforesaid order, the appellant was required to pay a sum of Rs.70 lakhs in four equal monthly instalments starting from 1-8-1992. The appellant deposited the first instalment in the sum of Rs.17.50 lakhs and defaulted in paying the remaining three instalments. When this was brought to the notice of the High Court, the High Court vacated that order. Subsequently, the order dated 1-8-1993 was passed which records the vacation of the order passed earlier and permitted the Customs Authorities to encash the bank guarantee.

4. The relevant portion of the said order reads as under:
"In the result it is clarified and directed that the interim relief granted earlier has stood vacated pursuant to the order passed by this Court on 18-9-1992 inasmuch as the Company has not deposited the amount of Rs.70 lakhs as agreed and directed. It is further directed that the Union of India, Collector of Customs, Ahmedabad, and Assistant Collector of Customs, Kandla Port, Kutch, will be at liberty to encash the bank guarantee of Rs.1,45,27,079 (Rupees one crore forty - five lakhs twenty - seven thousand seventy - nine only) furnished by the Company. However, it is clarified that the Department will give credit to the opponent company of the amount paid by it as and by way of deposit in this Court. The applicant Union of India will be at liberty to withdraw the amount deposited in this Court. Rule made absolute accordingly."

5. The appellant filed the special leave petition against the said order which was also dismissed by this Court on 10-9-1993, inter alia, observing that it was not a case for interference with the order of the High Court as the appellant had defaulted in the matter of payment of instalments. The bank guarantee was, however, encashed to cover the amount up to Rs.70 lakhs, as for encashment of