William S. Chadwick, Jr., Executive Vice President and Chief Operating Officer of Ensco plc, will retire from the company effective 31 August 2012. Mark Burns, currently Senior Vice President – Western Hemisphere, will succeed Mr. Chadwick as Executive Vice President and Chief Operating Officer. “Bill has been a tremendous force within Ensco, and has helped guide our company from its inception through its growth into a premier offshore drilling company,” said Dan Rabun, Chairman, President and CEO. “His focus on safety, operational excellence and efficiency has shaped our culture and helped make us the driller of choice in the industry. We wish Bill the very best in his well-deserved retirement.” Mr. Chadwick joined Ensco in June 1987 as one of the organization’s first employees and served in leadership positions throughout his 25-year tenure. He was elected to his current position in January 2006. “It has been my privilege to be a part of Ensco for the last 25 years and to play a role in making Ensco the industry leader it is today,” said Mr. Chadwick. “It has been a joy to work with such a group of dedicated and skilled employees – truly the best in the world. And I am confident that the organization will continue to thrive and achieve even greater heights in the future with Mark as Chief Operating Officer.” Mr. Rabun noted, “Mark is a natural leader and an outstanding executive who is respected throughout our industry. Mark currently reports to Bill and we anticipate a very smooth transition.” Mr. Burns was named Drilling Contractor of the Year in 2007 by the International Association of Drilling Contractors. Mr. Burns joined Ensco in 2008 and became Senior Vice President—Western Hemisphere last year at the time of the acquisition and has been responsible for managing Ensco’s largest business unit, North and South America, and integrating a new business unit, Brazil. He will relocate from Houston to Ensco’s headquarters in London.