Using option panel entry for category ID

I’m trying to create a theme where the user can type in the ID number of a certain category, and it will then load that category into a certain section.

I have created an option panel in admin with the name:

fareham_film_category_id

I usually use this code for tellign it the category:

<?php $my_query = new WP_Query('showposts=5&offset=0&cat=4'); ?>

I am trying this, but only get a white screen 🙁

<?php $my_query = new WP_Query('showposts=5&offset=0&cat=<?php echo get_option('fareham_film_category_id'); ?>'); ?>