The Information Commissioner's Office (ICO) has given a new directory enquiry service for mobile phone numbers the go-ahead, despite concerns raised by privacy campaigners.

The 118 800 mobile directory will launch on June 18. For a £1 charge users will be put through to a name they request, even if they don't have the mobile number, although the recipient must first agree to take the call and the user won't be issued with the contact number.

Numbers can be removed from the service by sending a text or calling a standard rate number, but this could take up to four weeks to take affect.

According to Connectivity, the firm behind the service, the 42 million telephone numbers have been bought from market research firms.

Chief executive of 118 800 Raj Raithatha told The Telegraph: "If you look at the service, you will see that we do not give out mobile numbers. We facilitate a service - it's a core connect service. The short term concern is to overcome people's concerns about privacy - which is entirely right - so it is important to stress that people will be allowed to opt out at any stage.

"We have a list of selected files of mobile numbers that are exempt which include Government ministers and celebrities," he added.

However, privacy campaigners warned mobile phone owners would be concerned to find their details included without their consent.

Despite this, the ICO gave the directory the green light saying it was "privacy friendly in that it will only connect people when the recipient agrees to take the call and even then it will do so without divulging their number".

"We made it absolutely clear to Connectivity that they should not use numbers where there was any doubt about whether the consumer was happy for their information to be used in this way," added the ICO.