LONDON (Reuters) - Spain's Telefonica (>> Telefonica SA) said on Friday that finance executive Mark Evans would replace Ronan Dunne as the boss of its British network operator O2 on August 1.

Evans, who joined O2 in 2012 as chief financial officer, takes the top position two months after European regulators blocked CK Hutchison Holdings (>> CK Hutchison Holdings Ltd) planned acquisition of O2.

Dunne, the UK telecommunication industry's longest serving chief executive who has led O2 since 2008, will step down from the UK board and Telefonica SA executive committee on July 31, the company said.

(Reporting by Paul Sandle; editing by Sarah Young)

Stocks treated in this article : Telefonica SA, CK Hutchison Holdings Ltd