(1) Subject to any rules made in this behalf, a National Service Tribunal may require any establishment (including a notified establishment) to post before a specified date and to keep posted, on its premises notices intimating that—
         (a) no person included within the definition of technical personnel who is employed in the establishment shall at any time after the posting of the notice, leave his employment without the previous permission in writing of the National Service Tribunal;
         (b) if the National Service Tribunal refuses such permission, that tribunal may lay down, subject to the prescribed conditions, the terms of service on which the employer shall continue to retain him in employment;
         (c) if any such person leaves his employment without the previous permission in writing of the Tribunal as aforesaid he may be directed by the Tribunal to return to his employment.
     (2) After notices referred to in sub-section (1) have been posted on the premises of any establishment (including a notified establishment), no employer in the establishment shall engage, discharge or dismiss any person included in the definition of technical personnel except in accordance with rules made in this behalf.