The default Google search built into Firefox (at least in British builds) goes off to google.com and is then redirected to google.co.uk. Problem is, sometimes the redirection stops working and it stays with google.com — usually clearing cookies solves this problem. This means you lose the benefits of country-specific search. Installing this Google UK Search Provider will make sure that searches from the Firefox search bar go to Google UK every time. Also works with IE 8 (and any browser that supports OpenSearchDescription files).