The BBC has its design guidelines on the public sphere. I am particularly interetested on what they call Visual Language, the guidelines for the web.
The document, which is now on its version 1.06 (you can download the PDF here: Visual Language Guidelines v1.0.6), shows the grid behind, the way you can do flexible layouts with it, how the masthead and footer are created and more details, like text/object indentation, images sizes and ratios, media player sizes, advertising, etc.
It’s a concise document where you can clearly see how a page for the BBC.co.uk should be done.
Thanks to the BBC team for making this document available to the public.