Most of our page assets are served from sub-domains of bbci.co.uk (rather than bbc.co.uk or bbc.com). This is a conscious decision which has both security and performance benefits. We mandate that cookies are never set on bbci.co.uk, whereas bbc.co.uk and bbc.com are allowed to contain cookies. Since no cookies are sent with requests to bbci.co.uk, there is less chance of cookie data leakage and also the HTTP requests and responses contain fewer bytes of data, which results in increased performance.