Where an assessee, upon receiving a notice under section 148, did not file a return of income but instead filed a writ petition challenging the notice on the ground that it was unsigned (a defence raised for the first time), the High Court held that the writ petition was not maintainable. The Court observed that the assessee should have raised the objection regarding the unsigned notice in its reply to the Assessing Officer and followed the procedure laid down in GKN Driveshafts (India) Ltd. (.)  Consequently, the Court declined to exercise its writ jurisdiction and directed the assessee to file the return of income along with all objections, including the validity of the notice, before the Assessing Officer for disposal via a speaking order.(AY. 2005-06)