Dunne, who is currently O2 chief financial officer, will begin the role on February 1, 2008 and will also join the board of Telefonica O2 Europe.
Dunne joined O2 in 2001 as head of finance prior to the group’s de-merger with BT. He has previously worked as head of strategic finance and integration at Exel plc and held various other senior financial roles in banking and the corporate sector.
Matthew Key said: “I am delighted that we are able to promote one of our key executives to this important role. Ronan has been an exceptional CFO, with an outstanding track record and business insight.”