1. This appeal is directed against the order of the learned single Judge in W.P.No. 3534 of 1989, dated 38. 1994. The writ petition relates to the action of the respondents in withdrawing the concessional rate of tariff on the ground that the petitioner was not eligible for availing the concessional rate because it is a branch unit of the appellant unit elsewhere. According to the petitioners, they established a unit at Hosur in or about April 1961, which was given the benefit of concessional tariff by the Court. The Board by letter dated 8. 1995, demanded payment of Rs. 2,36,767-83 on the ground that the petitioners’ unit at Hosur is nothing but a branch unit and therefore, they are not eligible for the grant of concession. Challenging this demand, it is contended that it is a new industrial undertaking and not a branch unit; that the action is vitiated by principles of natural justice; that the dispute as to whether the Unit at Hosur is a branch unit or a new industrial undertaking cannot be unilaterally decided by the respondents and that the respondents are estopped from denying the status of the petitioners’ unit as a “new industrial undertaking”.

2. The learned sin