A cookie is a small data file that is placed on your computer by your browser when you visit certain websites, including ours. They improve things by measuring how you use the website so we can make sure it meets your needs, to make the site work better for you and to give us useful information on the numbers of visits our site receives.
Cookies contain information about the use of your computer but don’t include personal information about you (they don’t store your name, for instance). Most browsers allow you to turn off cookies and this can often be done in the help section of your browser. Turning off cookies will however limit your online experience.
The relevant regulator in this area, the Information Commissioner's Office, has published guidance on the different kinds of cookies and what they are used for. The guidance, with Q&A, can be found here.