Oct. 12 (Bloomberg) -- Telefonica SA’s O2 mobile-phone unit will allow some clients to make calls over a WiFi network to any U.K. mobile or landline number.

The O2 Connect service will initially be available on Apple Inc.’s iPhone and devices using Google Inc.’s Android system, the company said in a statement today.

The trial, starting this month, will allow O2 to “explore the potential of delivering VoIP services to customers,” said Richard Porter, Head of Consumer Mobile Products of O2 in the U.K.

To contact the editor responsible for this story: Simon Thiel at sthiel1@bloomberg.net