Higher selection grade (BPS) granted due to fault of department—Whether salary and benefits paid due to such fault/error could be recovered—Locus poenitentiae, principle of—Estoppel—Petitioner (civil servant) was appointed as senior auditor in BPS-11—Subsequently petitioner was erroneously granted selection grade BPS-15 and started getting pay of such selection grade—Once the department realized its mistake, it reverted the petitioner back to BPS-11 and sought recovery of salary and benefits paid to him on the principle of locus poenitentiae–-Held, that for almost 9 years the petitioner served in selection grade BPS-15 and received the emoluments and benefits of such post—Selection grade BPS-15 was granted to the petitioner by the department itself and the petitioner apparently had no role in obtaining such post—When the petitioner performed the work of a higher post of selection grade BPS-15 for almost 9 years, then on the principle of locus poenitentiae the benefits paid to him, could not be recovered as said principle would not apply—Further the principle of estoppel would be applicable in the present case against the department from recovering the emoluments and benefits of BPS-15 from the petitioner—Petition for leave to appeal was converted into appeal and allowed.