A cookie is a small piece of information created by a website and sent to your browser. When your browser requests a page from a website, the site can create a cookie and send it to your browser along with the page. When your browser later asks the website for another page it will send the cookie back to the website so that it can "remember" important information such as whether you are signed in to the site and what pages you can access.
There are several varieties of cookie. Session cookies are only stored by the browser for as long as your session lasts. Persistent cookies are saved in your computer with an expiry date so that their information is available for days, weeks or even years. Performance cookies are persistent cookies set by analysis tools, such as Google Analytics, that help reveal how users interact with a website and ensure that their experience is a good one. If a web page has adverts or other content from other websites, those sites can set third-party cookies which may be used to track your browsing history. We recommend that you set your browser to disallow third party cookies.
For more details about cookies and details of how to delete and disable cookies you can visit www.aboutcookies.org.
We use two session cookies: “pra_user” records when a user is signed in, the user's information services and whether the user is a PRA Member; “praprg” is used to pass security tokens between requests and is deleted after each use.