(Telecompaper) Telefonica UK (O2) has confirmed that Chief Financial Officer (CFO) Mark Evans has been appointed as CEO to take over from Ronan Dunne on 01 August. He will also join the Telefonica Executive Committee. Dunne has been CEO of Telefonica UK since January 2008, and indicated in September 2015 that he planned to step down from the UK Board and Telefonica Executive Committee. He will step down from the Board on 31 July, but continue to support the business until September. Evans also manages the giffgaff brand, which is a wholly owned subsidiary of Telefonica, and is Chairman of Tesco Mobile.