118800 is a site some may find useful, but I personally feel is taking things a bit far. A directory listing mobile phone numbers for the UK, it boasts. I'm not in favour however, so to the nitty gritty. Short and sweet.
Enter your mobile on this page , then the code is sent to your phone by text message.
Put that in the box and you're exempt from their effectively unathorised publication of your mobile number.