How to get page ID from inside header.php ?

Hi,

I’m trying to get the value of a custom field from within header.php. I ‘ll then use the value to decide which images to display in a banner inside the header.

Just to clarify, this is for a page, not a post.

I can use the following code OK within page.php

<?php echo 'custom data: ' . get_post_meta(get_the_ID(), 'banner_images', true); ?>

but if I try it inside header.php then nothing is returned by get_post_meta()

I’ve tried using $pot->ID to retrieve the page id, but that doesn’t work either.

I don’t want to hard-code the page id, as that kind of defeats the object.

Any suggestions?

Cheers,

Nick