Changing drupal project folder breaks links I have a drupal project working in the server home directory. I want to move this from the server home directory to a subdirectory to make way for other drupal projects.

I move the whole drupal project from www/var/html to www/var/html/old_project

I change the $base_url in the drupal project settings to http://localhost/old_project

In the web browser I navigate to localhost/old_project. The home page displays but image links are broken. Links are broken to any other page I navigate to on the site. I can see that the urls are missing the .../old_project/...' part of the url.

Why is it omitting this and how can I fix it?

EDIT

Even when I access the urls directly typing in the '.../old_project/...' part I get 404 errors.

I have also tried adding RewriteBase /old_project in the .htaccess in /sites/default/files/ and rebuilding the registry. 

Many thanks
You need to rebuild theme registry. Download Registry rebuild module.
and apply the following command drush @site rr