How do I prevent displaying the Custom Sidebars column in the Pages Listings Page in WP Admin

How do I prevent displaying the Custom Sidebars column in the Pages Listings Page in WP Admin?

http://concept896.designsteps.co.uk/wp-admin/edit.php?post_type=page

Also in the Posts Listings Page in WP Admin:

http://concept896.designsteps.co.uk/wp-admin/edit.php