How to add a meta tag to one page only

Hi,

I want to add something into the head section of just one specific page in my blog (a page, not a post), a meta tag like this —

<meta http-equiv='Refresh' content='0;url=javascript:history.go(-1)'>

I’ve tried the following in my header —

<?php
if (is_single()) {
     if ($custom_header = get_post_meta($post->ID, 'custom_header', true)) {
     echo $custom_header;
     }
}
?>

— and created a custom field for that page called custom_header with the meta as the value, but that hasn’t worked. How can I add that meta tag to just one specific page?

Thanks.