As you may have heard in the news there is a new service called 118800 which acts as a directory for mobile phone numbers.
In my opinion this service is an infringement of civil liberties as it is giving out phone numbers without the permission or registration of phone owner.
To go ex-directory go to http://www.118800.co.uk/. The service is down at the moment, presumably from the avalanche of requests from people to be removed.