The first directory enquiry service for UK mobile phone numbers is due to launch on 18 June.
Connectivity, the company behind the 118800 service, has given assurances that privacy will be protected, but consumer watchdog forums are already buzzing with complaints, and privacy groups are up in arms.
Unlike a fixed-line enquiry service, 118800 will not give out numbers. Instead, a user will provide an operator with the name and home town of the party they wish to contact. If the name is in the 118800 database, the operator will call the number and ask permission to connect the caller.
In the event that the called party fails to answer, users can elect for the operator to leave a voice message or send an SMS. Calls to 118800 will be charged at 14p per minute, chargeable per second, plus 69p per call.
A web-based service which uses SMS to request the called party to contact the caller will be launched on the same day on 118800.co.uk charged at £1 per search.
Some members of the public who have seen early publicity for the service have not reacted well in public forums.
"I do not want my mobile numbers on your database," said one contributor to the mobile phone forum on MoneySavingExpert.com.
Privacy groups are also wary of the service. Even Simon Davies of Privacy International, who was hired as a consultant by Connectivity during the development of the service, told The Times that there are "fundamental privacy issues".
"The company needs to be far more specific about where it acquired the numbers on its directory, and from what sources," he said.
Connectivity is adamant that it built the 118800 database from legitimate sources, and has done its utmost not to include anyone under the age of 18 on the database.
Anyone can opt out of the database at anytime by texting 'e' for ex-directory to 118800. The first time anyone is contacted by the service after it launches, they will be given the option to de-list.