In May 2011 there was an amendments to the 2003 EU e-privacy directive. This required websites to gain user consent for the use of tracking technologies, the most common of which are 'cookies'.
Updated advice from the information commissioner have been issued just hours before the new regulation was to come into force. The largest change was that they now state websites can imply that the users have consented to use their cookies.
“While explicit consent might allow for regulatory certainty and might be the most appropriate way to comply in some circumstances this does not mean that implied consent cannot be compliant.”
If you wish to rely on this implied consent then you need to be satisfied that your users understand that their actions will result in cookies being set. Without this understanding you do not have their informed consent.
Creo Interactive Ltd