Necessary

Essential for the site to work and to remember your cookie choice. They cannot be switched off and are not used to track you.

Measurement

They tell us how many people visit each page and where they come from, in aggregate. We use them to decide what to improve. If you reject them, the site works just the same.

Advertising

These would measure how well adverts perform. We do not use any at the moment: the option is here in case we add them later.