The Principal Commissioner invoked section 263 to revise a reassessment order by directing the Assessing Officer to examine issues and judicial decisions which were neither part of the reassessment proceedings nor the assessment records. The Tribunal held that the jurisdiction under section 263 can be exercised only where the assessment order is both erroneous and prejudicial to the interests of the Revenue. Since the Assessing Officer had confined the reassessment to the issues forming part of the recorded reasons for reopening and had conducted the necessary enquiries on those issues, the Commissioner could not direct investigation into unrelated matters or rely upon material outside the assessment records. The revisionary order was, therefore, quashed. (AY. 2012-13).