N.L. UNTWALIA, J.

(1) IN these appeals by certificate the question for determination is whether the exercise of the power of revision under Ss. (3) of S. 20 of the Bengal Finance (Sales Tax) Act, 1941 as extended to the Union Territory of Delhi hereinafter called the Act is subject to the period of limitation provided in Ss. (2a) of S. 11 or S. 11 A of the said Act. The requisite facts lie in a narrow compass and may usefully be stated at the outset.

(2) THE appellant who was carrying on the business of execution of building contracts was assessed to sales tax under the Act by the Sales Tax Officer for the year 1955-56 by an order of assessment made on 23/11/1959. The appellants appeal before the Assistant Commissioner of Sales Tax succeeded in part. He held that the assessment for the first two quarters of the year 1955-56 was invalid having been made out of time. The case was, therefore, remanded to the Sales Tax Officer for a fresh assessment in respect of the third and fourth quarters of the year. The Sales Tax Officer in pursuance of the appellate order of remand dated 11/02/1960 passed afresh assessment order on 21/03/1960. The Commissioner, however, after notice dated 21/07/1960 to the appellant, by his order dated 29/07/1960 revised the appellate order of the Assistant Commissioner in exercise of his power under S. 20(3) of the Act. He held that no part of the assessment for the year 1955-56 was barred and directed a fresh assessment to be made. A fresh assessment for all the four quarters was accordingly made by the Sales Tax Officer on 24/09/1960. The appellant filed two Writ Petition in the Delhi High court challenging the order made in revision by the Commissioner and the fresh assessment order passed by the Sales Tax Officer in pursuance thereof. A learned Single Judge of the High court allowed the writ applications on 2/04/1969 and quashed the impugned orders. The respondents took up the matter in letters patent appe.al and succeeded before a bench of the High court. Hence these appeals by the assessee.

(3) MR. F. S. Nariman appearing for the appellant contended:

(1) That the appellate and the revisional authorities must exercise (their appellate or revisional power within the period prescribed under Ss. (2a) of S. II of the Act.. If their orders are final orders of assessment then directly they are exercising their powers under Ss. (1) or (2) of S. 11. In case their orders are of remand for fresh assessment to the assessing authority then also they must pass their orders within the periods aforesaid although under the proviso added in 1959 the assessing authority may have a further period of 4 years or 6 years, as the case may be, for passing a fresh assessment.

(2) That the Commissioner while exercising the power in revision cannot overstep and ignore the period of limitation of 3 years provided in S. 11A of the Act.

(3) That the authority mentioned in S. 11, 11A and 20(3) being the Commissioner, the Commissioner is subject to the period of limitation provided in S. 11 and 11A even when exercising the revisional power under S. 20(3).

(4) That in any view of the matter the revisional authority must exercise the power in a reasonable manner and within a reasonable time. It cannot exercise the power of revision, suo moto, after a long lapse of time at its sweet will and pleasure.

(4) UNDER S. 3 of the Act, a hierarchy of officers has been constituted by the Chief Commissioner namely, the Commissioner of Sales Tax, Sales Tax Officers and others to assist him. S. II of the Act deals with assessment of tax. The Sales Tax Officer exercising the powers as an officer to assist the Commissioner under S. 11(1) of the Act can proceed to assess the amount of the tax due from a registered dealer within 18 months of the expiry of a particular period. A dealer who has been liable to pay tax under the Act but has failed to get himself registered can be assessed to tax under Ss. (2). Then