O2 has picked the man who will replace Matthew Key as its UK CEO. Chief financial officer Ronan Dunne will step in to Key’s post in the new year when Key succeeds Peter Erskine as CEO across the whole of Telefonica/O2’s European operations. Dunne joined the then BT/Cellnet in 2001 and became CFO in 2005. Key’s promotion to the new role was announced in November.