Judgment :- GOVINDASAMY, J. The Petitioners-society are assessees on the file of the Deputy Commercial Tax Officer, Amandakarai Assessment Circle, Kilpauk Garden Road, Madras, the third respondent herein. The petitioners were assessed to tax for the assessment years as detailed below : 1975-76 ... Rs. 33, 065.00 1976-77 ... Rs. 33, 332.00 1977-78 ... Rs. 24, 093.00 1978-79 ... Rs. 33, 149.00 1979-80 ... Rs. 19, 888, 00 1980-81 ... Rs. 19, 719.24 As against the orders of these assessments, the petitioners have failed to prefer appeal before the appellate authority for the assessment years 1975-76, 1976-77 and 1980-81. In respect of the other assessment years, namely, 1977-78, 1978-79 and 1979-80, the appeals preferred by the petitioners before the Sales Tax Appellate Tribunal (Main Bench), Madras, were allowed in Tribunal Appeal Nos. 1763, 1764 and 1765 of 1981 on August 6, 1982, holding that the transaction effected by the writ petitioners did not represent sales and hence the petitioners were not liable to sales tax. The petitioners alleged that the petitioners filed appeals for the years 1975-76, 1976-77 and 1980-81 for the reason that the petitioners believed that the principles stated by the Sales Tax Appellate Tribunal would be applicable and followed by the assessing authorities, the second and third respondents herein. It is since the assessing authority did not follow the principles set out by the Sales Tax Appellate Tribunal, the petitioners have filed revision petition invoking the suo motu power available under section32 of the Tamil Nadu General Sales Tax Act, 1959 2. The learned counsel for the petitioners contended that the writ petitioners filed revision petitions before the second respondent herein on September 29, 1982, even before the amendment was effected, in respect of section32 of the Act. In view of the fact that the writ petitioners have filed revision petitions even before the amendment of the Tamil Nadu General Sales Tax Act under section 32, the revisional authority should have disposed of the revision petitions on merits. The rejection of the revision petitions on the ground that the subsequent amendment had taken away the right of the revisional authority to exercise the suo motu power in respect of matter which are prejudicial to the interests of Revenue, is not sustainable in law. In support of the above contention, learned counsel for the petitioner refers to the decision of a Full Bench of this Court in L.Ar. In support of the above contention, learned counsel for the petitioner refers to the decision of a Full Bench of this Court in L.Ar. Arunachalam Pillai and Sons v. State of Tamil Nadu reported in 1980 (45) STC 109 , wherein the Full Bench of this Court held that the suo motu power of revision of the Deputy Commissioner under section32 of the Tamil Nadu General Sales Tax Act, 1959, can be invoked by an assessee. This Court also observed that the Deputy Commissioner could not decline to exercise his revisional jurisdiction under section 32 on the ground that the assessee was not diligent in filing an appeal. If he was diligent in preferring an appeal, there would have been no occasion or need for the assessee to invoke the jurisdiction of the Deputy Commissioner under section32 of the Act. As an appeal excludes the jurisdiction of the Deputy Commissioner under section 32, and as the appellate power and revisional power of the Deputy Commissioner are mutually exclusive, the exercise of revisional power under section 32 cannot be declined on the ground of lack of diligence in filing an appeal. 3. In view of the aforesaid view of this Court, the exercise of the revisional power under section32 of the Act by the second respondent cannot be declined even on the ground that subsequent amendment takes away the powers of the revisional authority. Admittedly, at the time when the revision petitions were filed by the writ petitioners the second respondent was vested with the power so to say suo motu power to revise the orders of this Court (sic) and as such the second respondent ought to have entertained the revision petitions filed by the writ petitioners before the amendment and having allowed the writ petitioners to file revision petitions before the amendment, there is no justifiable reasons to reject the entertainment of the said revision petitions by reason of the fact that subsequent amendment came into effect after the revision petitions were filed by which the powers of the revision had been taken away. Such a contention is not sustainable in law. Such a contention is not sustainable in law. That apart, the revisional authority should have provided an opportunity to the writ petitioner to satisfy the revisional authority that the revision petitions should have been entertained by reason of the fact that the revision petitions have been filed by the writ petitioners before the amendment came into effect, The failure to issue notice and failure to provide opportunity to the writ petitioners vitiates the impugned order by reason of the fact that the well-known maximum of audi alteram partem was rejected to the petitioner so as to comply with the concept of principles of natural justice. 4. In view of the above, the impugned order is liable to be quashed and it is quashed, but with the direction to the second respondent to entertain the revision petitions filed by the writ petitioners and to decide the matter on merits as per law held by the Sales Tax Appellate Tribunal in similar matters. With these directions, the writ petitions are ordered. No costs.Writ petitions allowed.