Chief Engineer stating that the petitioners had continued against leave vacancies from 17.9.1999 and 7.6.2002 respectively. In the absence of any claim by the petitioners for regularization with effect from any anterior date, I am of the considered opinion that such recommendation cannot have any binding effect on the decision of the Board, which was the competent authority for considering the claim for regularization. Since the petitioners were only ad hoc appointees whose claim for regularisation had once been rejected by a Division Bench of this Court, I am of the opinion that their claim could, at best, arise only from 19.08.2008, the date of Exhibit P3 judgment. The said judgment was complied with and Exhibit P6 order was issued in December, 2010, regularizing the petitioners' service from the date of the said order. It is trite law that in the absence of a clear right for regularization in service with effect from an anterior date, an order of regularization, which is essentially a concession granted to ad hoc appointees, can have only prospective effect and such orders cannot affect the accrued rights of appointees