Cookies are small text files which are stored on your device and contain plain text. In all cases, cookies themselves do not have access to your device and can not ‘run’ like normal programs on your device.
Websites are ‘stateless’; each page exists in isolation, and so information can only be passed through URL parameters (the bits of text you sometimes see after a website address which start with a question mark), form parameters, or cookies. Cookies are the ‘cleanest’ and least intrusive (from a user’s point of view) and easiest to manage (from a website developer’s point of view) method for maintaining ‘state’ throughout your visit to a website.
Without the use of a cookie, you would be asked for the information stored in the cookie or to log in on every single page of the website!
Session cookies are temporary cookies, which exist for the duration your browser is running. When your browser is closed, the session cookies are lost. These are typically used to identify users when they log in. As the user browses the site, the web application knows which user is logged in and can tailor the experience accordingly and provide user-specific information, as appropriate.
Permanent cookies are permanent insofar as they remain on your device even after you close your browser. This makes them unsuitable for security purposes (such as session cookies), but perfect for storing personal preferences, such as your country and language preference (for formatting dates, times, etc.). Without these kind of cookies, you would have to set such preferences on each visit to the website.
Third party cookies are cookies (session or permanent) which are created not by our web applications, but by external agencies or companies. We use such cookies for tracking how visitors use our site, which enables us to improve our site content by seeing which pages are popular and how visitors navigate through the site. Such cookies are not created by our Web applications, but by the third parties. As such, the names of these may vary from time to time. Third party cookies do not personally identify you, but merely allow the third parties (and us in the case of analytics services) to keep a record of how you use the site.
Any cookies can be blocked or removed from your browser at any time by following the relevant procedure specific to your browser. You retain full control of which cookies exist on your computer. You may also block the creation of cookies from all or individual sites.
You may block cookies on this site, but the site may not function as designed and you will be unable to log in where appropriate or retain any user preferences, so information may appear in the wrong locale or be unavailable.
Other local/session storage keys may be set via the third-party services mentioned above. As with cookies, local and session storage may be blocked by your chosen browser. Consult your browser provider for further information.
Further information and advice, including on how to manage and block cookies, is widely available online.