There is no doubt that after passing of the original assessment order, the primary (i.e. original proceedings) had come to an end and attained finality and, therefore, outcome of the same cannot be disturbed, and therefore, the original assessment order framed to conclude the primary proceedings had also attained finality and it also cannot be disturbed at the instance of the assessee, except as permitted under the law and by following the due process of law. Under these circumstances, it can be said that effect of the original assessment order cannot be erased or modified subsequently. In other words, whatever tax liability had been determined in the original assessment order that had already become final and that cannot be sought to be disturbed by the assessee. But, the issue that arises here is that if the original assessment order is illegal in terms of its jurisdiction or if the same is null & void in the eyes of law on any jurisdictional grounds, then, whether it can give rise to initiation of further proceedings and whether such subsequent proceedings would be valid under the law as contained in Income Tax Act? It has been vehemently argued before us that the subsequent proceedings (i.e. collateral proceedings) derive strength only from the order passed in the original proceedings (i.e. primary proceedings). Thus, if order passed in the original proceedings is itself illegal, then that cannot give rise to valid revision proceedings