I've switched comments off on posts by unticking in screen options.
I am now receiving this error where the comment box used to be:
Warning: call_user_func() expects parameter 1 to be a valid callback, function 'custom_comment' not found or invalid function name in /home/website/public_html/wp-includes/comment-template.php on line 1334
Can someone please help me with this? I have no idea what the problem is!