How is WordPress redirecting/rewriting my URL?

i'm running a wordpress free classified w开发者_StackOverflow社区ebsite and the address is http://www.gosell.co.uk what i need is if a user from london open this url then it should be concatenated with http://www.gosell.co.uk/longon how is that possible? shall i make a new function or wat? Thanks in advance.

Hook into init action (http://codex.wordpress.org/Function_Reference/add_action), detect where is your visitor from using some of available geoip solutions, and then use wp_redirect to redirect to the right url...