3D Text flicker on camera movement using custom shader

I was having issues with 3D text being displayed through other objects. This is a well known issue, and I used the steps in the wiki to overcome this problem.

See: http://wiki.unity3d.com/index.php?title=3DText

This method works for displaying the text correctly behind objects, however when I move the camera, the text flickers badly - nothing else in the scene flickers - just the text, which looks terrible.

How can I get around this issue? Please let me know if I need to post anything else here.

Sorry I discovered I was drawing the text too low inside other objects.