Complex privacy rules surrounding mobile phone numbers and their ownership meant that Connectivity, the company operating the 118 800 service over the phone and on the web, had to adopt an unusual approach to supporting directory assistance enquiries.
Instead of callers or internet users being given the number, their contact details were taken and the mobile phone user was called or texted, and a request to complete the call was made.
Amid a raft of negative publicity and statements by the firm that mobile phone users who wanted their details removed from the database could have them removed on request, it seems the 118 800 service - the first to offer mobile and fixed line phone numbers in the UK - proved to be uneconomic in its present form.
After initially saying the service was operating within the rules, the Office of the Information Commissioner announced last week it was mounting an investigation into the length of time before mobile users requesting their data be removed from the database had their numbers deleted.
A spokesperson for the ICO told Infosecurity that the investigation into the service had already started and would likely continue, since the downing of the 118 800 service is apparently temporary.
The investigation will also look at how Connectivity is - or was - complying with the provisions of the UK's data protection and privacy legislation.
Unconfirmed reports suggest that this was the final straw for Connectivity, which withdrew the service last Friday.
As news of the `temporary' withdrawal of the service broke over the weekend, it transpired that Connectivity had actually bought in the details of the estimated 15 million UK mobile phone users on its database from third parties and that some of the data may have been out of date.
A notice on the website says that Connectivity is undertaking some major developments to its 'Beta Service' to improve the experience for customers.
"So the service isn't available at www.118800.co.uk or by phone. We'll be back as soon as possible."
Calls by Infosecurity to Connectivity for an update on when the `beta service' will be resumed were not returned at press time.